INTERSECTION CONTROL EVALUATION

Transcription

1 INTERSECTION CONTROL EVALUATION Trunk Highway 22 and CSAH 21 (E Hill Street/Shanaska Creek Road) Kasota, Le Sueur County, Minnesota November 2018

2 Trunk Highway 22 and Le Sueur CSAH 21 (E Hill Street/Shanaska Creek Road) Intersection Control Evaluation Kasota, Le Sueur County, Minnesota I hereby certify that this report was prepared by me or under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. Mike Bittner, PE, PTOE Date: 11/28/2018 License No: Approved: MnDOT District 7 Traffic Engineer Date MnDOT District 7 State Aid Engineer Date ICE Report TH 22 and Le Sueur CSAH 21 i

3 Contents Background and Study Area... 1 Roadway Characteristics... 1 Study Intersection Configuration... 1 Access Spacing... 1 Traffic Volumes... 1 Directional Traffic Distribution... 3 Major Approach Versus Minor Approach Volumes... 3 Traffic Operations... 3 No Build: Two-Way Stop Control... 3 Signal Control... 4 Roundabout Control... 5 Truck Considerations... 5 Reduced Conflict Intersection... 6 Rural Intersection Conflict Warning System... 7 Queue Analysis... 7 Crash History... 8 Summary and Recommendation... 8 ICE Report TH 22 and Le Sueur CSAH 21 ii

4 Background and Study Area As part of the Trunk Highway (TH) 22 Corridor Study, intersection control revisions are being considered at the intersection of TH 22 and Le Sueur County State Aid Highway 21/ E Hill Street/Shanaska Creek Road (to be referred to as CSAH 21) in Kasota. The objective of this Intersection Control Evaluation report is to determine the optimal intersection control to improve future traffic capacity and reduce crash potential. When identifying potential traffic control options, consideration was also given to factors such as traffic control consistency along the corridor and planned corridor-wide improvements. For the study intersection, the following intersection control options were evaluated:» Two-way stop control (existing control)» Traffic signal» Hybrid Roundabout» Reduced conflict intersection The study area can be seen in Figure 1. Roadway Characteristics TH 22 is functionally classified as a principal arterial and CSAH 21 is classified as a major collector. At the intersection, each roadway has a posted speed limit of 55 mph. STUDY INTERSECTION CONFIGURATION The intersection of TH 22 and CSAH 21 currently is stop controlled on the CSAH 21 approaches. The lane configuration is:» Southbound: Two through lanes (truck climbing area), dedicated right- and left-turn lanes» Northbound: One through lane, dedicated right- and left-turn lanes» Eastbound: Dedicated right-turn lane, shared through/left-turn lane» Westbound: Dedicated right-turn lane, shared through/left-turn lane ACCESS SPACING North of CSAH 21, the closest access points are a sand/gravel pit access 1,360 feet (0.25 miles) to the north and Le Sueur County Road 45 3,340 feet (0.6 miles) to the north. South of CSAH 21, the closet access is Pearl Street, 1680 feet (0.32 miles) to the south. All of these adjacent access points are stop controlled on the minor approaches. Minnesota Department of Transportation (MnDOT) access spacing guidelines for rural principal arterials (Mn/DOT Access Management Manual [2008]) recommends 1-mile access spacing for primary full-movement intersections, and 1/2-mile access spacing for secondary intersections. Access spacing and associated access recommendations are being developed with the larger TH 22 Corridor Study. Traffic Volumes Existing and projected average daily traffic volumes (ADT) and peak hour turning movements at the study intersection can be seen in Figure 1. Existing volumes are 2017 traffic volumes that were collected for the TH 22 Corridor Study. Traffic projections for 2045 were developed through a review of historic traffic patterns and land use changes in the area average annual growth rates and 2030 ADT estimates were calculated based on 2017 daily intersection counts and assumed 0.8 percent to the north, 1.8 percent to the south, and 1.0 percent for both minor approaches. ICE Report TH 22 and Le Sueur CSAH 21 1

5 Figure 1 Study Area Details ICE Report TH 22 and Le Sueur CSAH 21 2

6 Based on discussions with the TH 22 corridor study Technical Advisory Committee, it has been established that 2045 traffic projections documented in this report reflect an aggressive growth scenario. As such, if less intense development occurs in the area than assumed for the 2045 traffic projections, 2030 traffic projections presented in this document could approximate 2045 projections in a more moderate growth scenario. DIRECTIONAL TRAFFIC DISTRIBUTION Under AM peak hour conditions, a roughly even split between northbound and southbound vehicles is expected through A slightly more unbalanced distribution is expected in the PM peak hour, with 2017 volumes indicating 55 percent of traffic traveling northbound, lowering to 53 percent travelling northbound by MAJOR APPROACH VERSUS MINOR APPROACH VOLUMES Daily mainline volumes on TH 22 exceed side street volumes on CSAH 21 by an approximate five-to-one ratio. During 2030 and 2045 AM peak hours, major approach volumes exceed minor approach left-turning/through movements by a ratio of around eight-to-one, increasing to an approximate 14-to-one ratio in the 2030 and 2045 PM peak hours. Traffic Operations Intersection level of service was evaluated for existing and future traffic conditions under each considered traffic control option. For two-way stop control and signal control, the Synchro 9/Simtraffic software was used and for roundabout control the HCS7 software was used. Each of these implement a level of service analysis methodology based on the Highway Capacity Manual methodology. Control delay thresholds for each level of service can be seen in Table 1. Table 1 Highway Capacity Manual Intersection Level of Service Thresholds Control Delay Unsignalized Signalized Level of Service (LOS) A > > B > > C > > D > > E > 50 > 80 F Per MnDOT Access Management Manual and FHWA guidance, LOS E or worse will be considered an operational deficiency where mitigation should be discussed. No Build: Two-Way Stop Control Under existing conditions, eastbound approach LOS C is experienced in the PM peak hour, which is within acceptable limits per MnDOT design standards. Minor approach LOS C is expected under 2030 conditions, lowering to LOS D on both minor approaches by Note: Delay presented in terms of seconds per vehicle Table 2 Two-Way Stop Control Delay and Level of Service Year AM Peak PM Peak NB SB EB WB Total NB SB EB WB Total A 3 A 12 B 11 B 5 A 3 A 3 A 16 C 12 B 4 A A 3 A 15 C 15 C 5 A 4 A 3 A 20 C 16 C 5 A A 4 A 30 D 28 D 9 A 4 A 5 A 29 D 27 D 7 A ICE Report TH 22 and Le Sueur CSAH 21 3

7 Signal Control Traffic signal warrants from the Minnesota Manual on Uniform Traffic Control Devices were evaluated under existing and projected traffic volumes. Minor approach right-turns were omitted from this analysis given the presence of eastbound and westbound right-turn lanes on CSAH 21. A traffic signal is not warranted under existing conditions; however, one is expected to be warranted by It is typical for a traffic signal or roundabout to be considered for MnDOT roadways when Warrant 1 is met (Scott Thompson MnDOT D7), which is expected to be at the study intersection under 2030 traffic volumes. Table 3 -Signal Warrant Analysis (2017 Volumes) Criteria Hours Met Hours Required Warrants Met Warrant 1a: Minimum Vehicular Volume 0 8 Not Met Warrant 1b: Interruption of Continuous Traffic 6 8 Not Met Warrant 2: Four-Hour Vehicular Volume 2 4 Not Met Warrant 3: Peak Hour 0 1 Not Met Warrant 7: Crash Experience 0* 8 Not Met Multi-way Stop Applications (MWSA) 0 8 Not Met *Hours meeting traffic volume component for Warrant 7 Table 4 -Signal Warrant Analysis (2030 Volumes) Criteria Hours Met Hours Required Warrants Met Warrant 1a: Minimum Vehicular Volume 2 8 Not Met Warrant 1b: Interruption of Continuous Traffic 12 8 Met Warrant 2: Four-Hour Vehicular Volume 8 4 Met Warrant 3: Peak Hour 3 1 Met Warrant 7: Crash Experience 2* 8 Not Met Multi-way Stop Applications (MWSA) 3 8 Not Met *Hours meeting traffic volume component for Warrant 7 Under signal control with the existing lane configuration, intersection LOS B is expected through 2045, with all approaches operating at LOS B or better. Note: Delay presented in terms of seconds per vehicle Table 5 Signal Control Delay and Level of Service Year AM Peak PM Peak NB SB EB WB Total NB SB EB WB Total A 6 A 13 B 13 B 9 A 9 A 7 A 12 B 12 B 9 A B 8 A 15 B 16 B 11 B 10 A 10 B 13 B 15 B 11 B ICE Report TH 22 and Le Sueur CSAH 21 4

8 Roundabout Control It is MnDOT s typical practice to consider roundabouts and signals when warrant 1 is met, and a signal is expected to be warranted by Under roundabout control, intersection LOS B is expected through 2045, with the lowest approach level of service being northbound LOS C during the 2045 PM peak hour. The assumed lane geometry for a roundabout is shown in Figure 2. Note the unique configuration with two southbound through lanes given the cross-section design at the study intersection. Figure 2 Assumed Roundabout Geometry Note: Delay presented in terms of seconds per vehicle TRUCK CONSIDERATIONS Table 6 Roundabout Delay and Level of Service Year AM Peak PM Peak NB SB EB WB Total NB SB EB WB Total A 6 A 7 A 10 A 8 A 12 B 5 A 6 A 7 A 8 A A 16 C 11 B 8 A 11 B 19 C 6 A 8 A 8 A 12 B Roundabouts have been successfully constructed on many Minnesota trunk highways, including two on the TH 22 corridor in Mankato. With proper roundabout design characteristics such as a sufficient inscribed circle diameter and truck aprons with curbs designed to prevent load shifting, trucks can navigate roundabouts without issue. According to information from MnDOT s Right of Way Mapping and Monitoring web application, an inscribed circle diameter of over 300 feet could be accommodated, with typical rural 2-lane entry roundabouts having diameters of 165 to 220 feet (MnDOT Road Design Manual Table A [2009]). ICE Report TH 22 and Le Sueur CSAH 21 5

9 Reduced Conflict Intersection Reduced conflict intersections (sometimes referred to as restricted crossing U-turn intersections) displace minor approach left-turns and through movements, instead having these movements turn right, then make a downstream U-turn to continue in the desired travel direction. Since there is no existing median and current recommendations identified in the TH 22 Corridor Study indicate resurfacing without major roadway expansion, a reduced conflict intersection may not be applicable at this location. Figure 3 Reduced Conflict Intersection Source: MnDOT While an atypical configuration, spot widening at the intersection could be an option to accommodate a median and a reduced conflict intersection. Such a configuration would vary from typical MnDOT designs since a reduced conflict at this intersection would have one through lane in each direction. Calculating total delays for each intersection movement under a reduced conflict configuration, westbound 2045 a.m. peak operations are expected to experience 21 seconds of additional delay compared to standard two-way stop control, lowering minor approach operations from LOS D to LOS E. Minor delay benefits are expected on the eastbound approach under a reduced conflict configuration, but eastbound LOS D is still expected in the 2045 p.m. peak hour. Given that a reduced conflict configuration is not expected to improve operations, this configuration was discarded from further analysis. If a decision is made to expand this section of TH 22 to four lanes, further analysis of a reduced conflict configuration may indicate improved operations. Note: Delay presented in terms of seconds per vehicle Table 7 Reduced Conflict Intersection Delay and Level of Service Year AM Peak PM Peak NB SB EB WB Total NB SB EB WB Total A 2 A 12 B 13 B 4 A 2 A 3 A 13 B 11 B 4 A A 3 A 21 C 49 E 11 B 3 A 5 A 25 D 22 C 7 A ICE Report TH 22 and Le Sueur CSAH 21 6

10 Rural Intersection Conflict Warning System Rural intersection conflict warning systems (RICWS) are supplementary warning devices to alert drivers on both the major and minor roadway approaches of potential intersection conflicts, with the primary goal to reduce fatal and serious injury crashes at these locations. The system can be placed on both the major and minor approaches or only on the major roadway. MnDOT research found that crash potential was reduced at low-volume rural intersections after RICWS implementation, however intersections with cross-products (minor approach daily entering volumes multiplied by major approach daily entering volumes) greater than 12 million were found to have increased crash frequencies with RICWS implementation. The existing cross product is over 20 million, therefore a RICWS is not an appropriate longterm solution at the intersection and was discarded from further analysis. Figure 4 Rural Intersection Conflict Warning System Major Approach shown on the left, minor approach shown on the right (Source: MnDOT) Queue Analysis Queue lengths were analyzed for standard two-way stop control, signal control, and roundabout control. A review of 95 th percentile queues under 2030 and 2045 conditions does not indicate that existing queue storage in turn lanes will be exceeded under two-way stop control or signal control. Roundabout control is expected to introduce more queuing on TH 22 than signal control, with a 95 th percentile northbound queue of 130 feet under 2030 PM peak conditions and almost 250 feet under 2045 PM peak conditions. Approach Direction Northbound Southbound Eastbound Westbound Existing Storage 2030 AM 2030 PM Table 8 95 th Percentile Queues 2045 AM 2045 PM 2030 AM 2030 PM 2045 AM 2045 PM 2030 AM Roundabout PM AM Left Thru Right Left Thru Right Left - Thru - Right Left - Thru - No Build Signal Right PM ICE Report TH 22 and Le Sueur CSAH 21 7

11 Crash History Crash data was obtained from MnDOT for the time period between January 2011 and December In the fiveyear period, five crashes were reported. Three head-on crashes, one right-angle crash, and one other type of crash (not specified) were reported in the study period. No crashes had reported injuries or fatalities. Using the critical crash analysis methodology which applies statistical analysis to determine if the difference in observed and typical crash rates for similar intersections is statistically significant, the intersection crash rate is not above the critical crash rate, but is above the statewide average. Based on research-supported crash modification factors, the following safety impacts are expected from traffic control revisions:» Signal control Total crash reduction of 44 percent Angle crash reduction of 77 percent Left-turn crash reduction of 60 percent Rear-end crash increase of 58 percent o Source: Harkey, et al. National Cooperative Highway Research Report 617: Accident Modification Factors for Traffic Engineering and ITS Improvements (2008)» Roundabout control Total crash reduction of 34 percent Injury crash reduction of 50 percent o Quin, et. al. Evaluation of Roundabout Safety (2013) Signal control is expected to reduce overall crash potential, including potential for angle and left-turn crashes since signalization reduces the need for potentially high-risk gap selection, especially given the 55 mph speed limit on TH 22. Intermittent red-phases for the major approaches will however increase rear-end crash potential. Rear end crash potential would be more significant for northbound vehicles since the closest signal to the south is seven miles away at CSAH 26 (227th Street) in Mankato. Roundabout control is also expected to reduce overall crashes, with a more significant reduction in injury crashes due to eliminating high-speed angle crash potential. Roundabouts also mitigate head-on collision potential, which was the most common crash type observed at the intersection. This is significant since across rural Minnesota trunk highways, head-on collisions make up only eight percent of total crashes but 20 percent of fatal crashes. While crash history does not indicate an issue with angle crashes, as traffic volumes increase gap acceptance will become more difficult, potentially resulting in more risky decision making for vehicles on the minor approaches. This is significant because across Minnesota two-way stop-controlled intersections, right-angle crashes contribute to around 55 percent of injury crashes, with no other crash type representing more than 10 percent of injury crashes. Summary and Recommendation All forms of traffic control that were carried through all analyses (two-way stop control, signal control, or roundabout control) are expected to provide acceptable operations through 2045, however signal control and roundabout control will provide better minor approach operations (LOS B or better) through Multimodal operations are expected to be similar under each scenario due to the rural nature of the intersection. ICE Report TH 22 and Le Sueur CSAH 21 8

12 Both a traffic signal or roundabout are also expected to reduce crash potential, but a roundabout is expected to have a more significant reduction in crash potential. A roundabout will also mitigate head-on crash potential unlike a signal, and head-on crashes were most common reported crash type at the intersection. Since a roundabout provides the lowest amount of delay, provides the greatest safety benefit, and can fit within available right-of-way, a roundabout is recommended for the future traffic control at the intersection of TH 22 and Le Sueur CSAH 21. Table 9 Summary of Analysis Alternative Assessment TH 22 and Le Sueur County Road 21 Traffic Operations Alternative Lane Configuration Traffic Control Warrants Safety Assessment Year Peak LOS* Do Nothing (TWSC) Preliminary Cost Estimate Existing AM B Crash rate above statewide average PM C 5 crashes in 5 years (no injuries) n/a 2030 AM C 3 head-on, 1 right-angle, 1 other PM C No Expected Change in Crash $ AM D Patterns Without Traffic Control PM D Revisions Traffic Signal Traffic Signal Warrants Met Warrant 1 (8-Hour) Warrant 2 (4-Hour) Warrant 3 (Peak-Hour) AM PM AM PM A A B B Total Crash Reduction of 44% Angle Crash Reduction of 77% Left-Turn Crash Reduction of 60% Rear-End Crash Increase of 58% $200 - $400 K Roundabout MnDOT Protocol is to Only Install Roundabouts If Signal Warrants or AWSC Warrants are Met AM PM AM PM A A A B Total Crash Reduction of 34% Injury Crash Reduction of 50% $1.2 - $1.4 M *Lowest approach LOS for TWSC, overall intersection LOS for all other traffic control ICE Report TH 22 and Le Sueur CSAH 21 9

13 INTERSECTION CONTROL EVALUATION Trunk Highway 22 and County Road 101 (480th Street) Le Sueur County, Minnesota November 2018

14 Trunk Highway 22 and Le Sueur County Road 101 (480th Street) Intersection Control Evaluation Le Sueur County, Minnesota I hereby certify that this report was prepared by me or under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. Mike Bittner, PE, PTOE Date: 11/28/2018 License No: Approved: MnDOT District 7 Traffic Engineer Date MnDOT District 7 State Aid Engineer Date ICE Report TH 22 and Le Sueur County Road 101 i

15 Contents Background and Study Area... 1 Roadway Characteristics... 1 Study Intersection Configuration... 1 Access Spacing... 1 Traffic Volumes... 1 Directional Traffic Distribution... 3 Major approach Versus Minor Approach Volumes... 3 Traffic Operations... 3 Crash History... 4 Queue Analysis... 4 Potential Traffic Control Options... 4 Signal Control... 4 Roundabout Control... 5 Reduced Conflict Intersection... 6 Rural Intersection Conflict Warning System... 6 Summary and Recommendation... 7 ICE Report TH 22 and Le Sueur County Road 101 ii

16 Background and Study Area As part of the Trunk Highway (TH) 22 Corridor Study, intersection control revisions are being considered at the intersection of TH 22 and Le Sueur County Road 101/480th Street (to be referred to as CR 101) between Kasota and Mankato. The objective of this Intersection Control Evaluation report is to determine the optimal intersection control to improve future traffic capacity and reduce crash potential. When identifying potential traffic control options, consideration was also given to factors such as traffic control consistency along the corridor and planned corridor-wide improvements. The following intersection control options were considered:» Two-way stop control (existing control)» Traffic signal» Roundabout» Reduced conflict intersection» Rural conflict warning system The study area can be seen in Figure 1. Roadway Characteristics TH 22 is functionally classified as a principal arterial and CR 101 is classified as a minor collector. At the intersection, each roadway has a posted speed limit of 55 mph. STUDY INTERSECTION CONFIGURATION The intersection of TH 22 and CR 101 currently is stop controlled on the CR 101 approaches. The lane configuration is:» Southbound: One through lane, dedicated right- and left-turn lanes» Northbound: One through lane, dedicated right- and left-turn lanes» Eastbound: One lane for all movements (no turn lanes)» Westbound: One lane for all movements (no turn lanes) ACCESS SPACING North of CR 101, the closest public access point is Midway Court which is 2,200 feet (0.4 miles) away. Township Road 140/470 th Street is one mile north of CR 101. South of CR 101, the closest public access point is Blue Earth County Road 2 (243rd Street) one mile away. All of these adjacent public access points are stop controlled on the minor approaches. MnDOT access spacing guidelines for rural principal arterials (Mn/DOT Access Management Manual [2008]) recommends 1-mile access spacing for primary full-movement intersections, and 1/2-mile access spacing for secondary intersections. Access spacing and associated access recommendations are being developed with the larger TH 22 Corridor Study. Traffic Volumes Existing and projected average daily traffic volumes (ADT) and peak hour turning movements at the study intersection can be seen in Figure 1. Existing volumes are 2017 traffic volumes that were collected for the TH 22 Corridor Study. Traffic projections for 2045 were developed through a review of historic traffic patterns and land use changes in the area average annual growth rates and 2030 ADT estimates were calculated based on 2017 daily intersection counts and assumed 1.8 percent to the north and to the south, 2.5 percent to the east, and 1.5 percent to the west. ICE Report TH 22 and Le Sueur County Road 101 1

17 Figure 1 Study Area Details ICE Report TH 22 and Le Sueur County Road 101 2

18 Based on discussions with the TH 22 corridor study Technical Advisory Committee, it has been established that 2045 traffic projections documented in this report reflect an aggressive growth scenario. As such, if less intense development occurs in the area than assumed for the 2045 traffic projections, 2030 traffic projections presented in this document could approximate 2045 projections in a more moderate growth scenario. DIRECTIONAL TRAFFIC DISTRIBUTION Under AM peak hour conditions, more TH 22 traffic is travelling southbound, with 61 percent of traffic travelling southbound in 2017, gradually becoming more balanced with 56 percent of AM peak traffic travelling southbound by Conversely, PM peak hour traffic is predominantly northbound, with approximately 54 percent of TH 22 travelling northbound under 2017, 2030, and 2045 conditions. MAJOR APPROACH VERSUS MINOR APPROACH VOLUMES Daily mainline volumes in 2030 and 2045 on TH 22 are expected to exceed minor approach volumes on CR 101 by an approximate 12-to-one ratio. During 2030 and 2045 AM peak hours, major approach volumes exceed minor approach left-turning/through movements by a ratio of around 10-to-one, increasing to an approximate 20-to-one ratio in the 2030 and 2045 PM peak hours. Traffic Operations Intersection level of service was evaluated for existing and future traffic conditions under two-way stop control using the Synchro 9/Simtraffic. Control delay thresholds for each level of service can be seen in Table 1. Table 1 Highway Capacity Manual Intersection Level of Service Thresholds Control Delay Unsignalized Signalized Level of Service (LOS) A > > B > > C > > D > > E > 50 > 80 F Per MnDOT Access Management Manual and FHWA guidance, LOS E or worse will be considered an operational deficiency where mitigation should be discussed. Under existing conditions approach LOS A is expected on the minor approaches. With no intersection geometry revisions minor approach LOS C is expected under 2030 conditions, lowering to LOS D in the PM peak hour by 2045, however this is still within acceptable limits. Note: Delay presented in terms of seconds per vehicle Table 2 Two-Way Stop Control Delay and Level of Service Year AM Peak PM Peak NB SB EB WB Total NB SB EB WB Total A 7 A 7 A 9 A 7 A 7 A 7 A 9 A 10 A 7 A A 8 A 15 C 15 C 8 A 8 A 8 A 14 B 20 C 8 A A 9 A 20 C 24 C 10 B 9 A 9 A 30 D 34 D 10 B ICE Report TH 22 and Le Sueur County Road 101 3

19 Crash History Crash data was obtained from MnDOT for the time period between January 2011 and December In the fiveyear period, nine crashes were reported. Six rear-end crashes, one sideswipe crash, and two run-off-the-road crashes were reported in the study period. Four crashes resulted in possible injuries and one crash resulted in a nonincapacitating injury. While six rear-end crashes were reported on TH 22, northbound and southbound left-turn lanes were installed at the intersection in 2015, which will mitigate rear-end crash potential. Queue Analysis A review of 95 th percentile queues under 2030 and 2045 conditions does not indicate that existing queue storage in turn lanes will be exceeded under two-way stop control or signal control. Table 3 95 th Percentile Queues Approach Direction Existing Storage Northbound Southbound Eastbound Westbound Potential Traffic Control Options Signal Control Traffic signal warrants from the Minnesota Manual on Uniform Traffic Control Devices were evaluated under existing and projected traffic volumes. Half of minor approach right-turns were considered in this analysis given the absence of eastbound and westbound right-turn lanes on CR 101. A traffic signal is not warranted under existing conditions or 2030 conditions per guidance in the Minnesota Manual of Uniform Traffic Control Devices, but the peak hour warrant is expected to be met by It is typical for a traffic signal or roundabout to be considered for MnDOT roadways when Warrant 1 is met (Scott Thompson MnDOT D7), which is not expected through As such, a traffic signal should not be considered unless future traffic volumes exceed what is currently projected through AM 2030 PM 2045 AM 2045 PM Left Thru Right Left Thru Right Left - Thru - Right - Left - Thru - Right - No Build ICE Report TH 22 and Le Sueur County Road 101 4

20 Table 4 -Signal Warrant Analysis (2017 Volumes) Hours Hours Warrants Criteria Met Required Met Warrant 1a: Minimum Vehicular Volume 0 8 Not Met Warrant 1b: Interruption of Continuous Traffic 0 8 Not Met Warrant 2: Four-Hour Vehicular Volume 0 4 Not Met Warrant 3: Peak Hour 0 1 Not Met Warrant 7: Crash Experience 0* 8 Not Met Multi-Way Stop Applications (MWSA) 0 8 Not Met *Hours meeting traffic volume component for Warrant 7 Table 5 -Signal Warrant Analysis (2030 Volumes) Hours Hours Warrants Criteria Met Required Met Warrant 1a: Minimum Vehicular Volume 0 8 Not Met Warrant 1b: Interruption of Continuous Traffic 2 8 Not Met Warrant 2: Four-Hour Vehicular Volume 1 4 Not Met Warrant 3: Peak Hour 0 1 Not Met Warrant 7: Crash Experience 1* 8 Not Met Multi-Way Stop Applications (MWSA) 0 8 Not Met *Hours meeting traffic volume component for Warrant 7 Table 6 -Signal Warrant Analysis (2045 Volumes) Hours Hours Warrants Criteria Met Required Met Warrant 1a: Minimum Vehicular Volume 0 8 Not Met Warrant 1b: Interruption of Continuous Traffic 4 8 Not Met Warrant 2: Four-Hour Vehicular Volume 2 4 Not Met Warrant 3: Peak Hour 1 1 Met Warrant 7: Crash Experience 2* 8 Not Met Multi-Way Stop Applications (MWSA) 1 8 Not Met *Hours meeting traffic volume component for Warrant 7 Roundabout Control It is MnDOT s typical practice to consider roundabouts if a signal is warranted, but since the eight-hour (Warrant 1) signal warrant is not expected to be met through 2045, a roundabout should not be considered at this time. ICE Report TH 22 and Le Sueur County Road 101 5

21 Reduced Conflict Intersection Reduced conflict intersections (sometimes referred to as restricted crossing U-turn intersections) displace minor approach left-turns and through movements, instead having these movements turn right, then make a downstream U-turn to continue in the desired travel direction. Since there is no existing median and current recommendations identified in the TH 22 Corridor Study indicate future expansion to a three-lane section with a continuous left turn lane, a reduced conflict intersection may not be applicable at this location. Figure 2 Reduced Conflict Intersection Source: MnDOT While an atypical configuration, spot widening at the intersection could be an option to accommodate a reduced conflict intersection. Such a configuration would vary from typical MnDOT designs since a reduced conflict at this intersection would have one through lane in each direction. Calculating total delays for each intersection movement under a reduced conflict configuration, some improvements are expected, with eastbound 2045 p.m. peak operations improved from LOS D to LOS C. Note: Delay presented in terms of seconds per vehicle Table 7 Reduced Conflict Intersection Control Delay and Level of Service Year AM Peak PM Peak NB SB EB WB Total NB SB EB WB Total A 0 A 12 B 13 B 2 A 1 A 1 A 12 B 11 B 2 A A 2 A 20 C 18 C 4 A 2 A 2 A 19 C 17 C 3 A From a safety perspective, MnDOT has found that reduced conflict intersections show a 42 percent reduction in injury crashes and a 70 percent reduction in fatalities. Data published by the FHWA shows smaller reduction in injury crashes of 22 percent and an overall crash reduction of 15 percent. It should be noted that most reduced conflict intersections are on four-lane median divided sections, so the crash benefits of a reduced conflict configuration on a two/three lane roadway section could be different. Rural Intersection Conflict Warning System Rural intersection conflict warning systems (RICWS) are supplementary warning devices to alert drivers on both the major and minor roadway approaches of potential intersection conflicts, with the primary goal to reduce fatal and serious injury crashes at these locations. The system can be placed on both the major and minor approaches or only on the major roadway. ICE Report TH 22 and Le Sueur County Road 101 6

22 MnDOT research found that crash potential was reduced at low-volume rural intersections after RICWS implementation, however intersections with cross-products (minor approach daily entering volumes multiplied by major approach daily entering volumes) greater than 12 million were found to have increased crash frequencies with RICWS implementation. By 2030 the volume cross product is expected to be nearly 14 million, therefore a RICWS is not an appropriate long-term solution at the intersection. Figure 3 Rural Intersection Conflict Warning System Major Approach shown on the left, minor approach shown on the right (Source: MnDOT) Summary and Recommendation Existing two-way stop control is expected to provide acceptable operations at the intersection of TH 22 and CR 101 through 2045, and the recent construction of left-turn lanes on TH 22 mitigates rear-end crash potential at the intersection. Multimodal operations are expected to be similar under each scenario due to the rural nature of the intersection. As such, no traffic control revisions are recommended unless a safety concern is identified in the future. ICE Report TH 22 and Le Sueur County Road 101 7

23 INTERSECTION CONTROL EVALUATION Trunk Highway 22 and Blue Earth CSAH 57 (North Riverfront Drive) Mankato, Minnesota November 2018

24 Trunk Highway 22 and Blue Earth CSAH 57 (North Riverfront Drive) Intersection Control Evaluation Mankato, Blue Earth County, Minnesota I hereby certify that this report was prepared by me or under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. Mike Bittner, PE, PTOE Date: 11/28/2018 License No: Approved: MnDOT District 7 Traffic Engineer Date MnDOT District 7 State Aid Engineer Date ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) i

25 Contents Background and Study Area... 1 Roadway Characteristics... 1 Study Intersection Configuration... 1 Access Spacing... 1 Traffic Volumes... 1 Directional Traffic Distribution... 3 Major Versus Minor Volumes... 3 Warrant Analysis... 3 Traffic Operations... 4 No Build: Two-Way Stop Control... 4 Continuous T Intersection... 4 Private Access Impacts... 5 Roundabout Control... 7 Truck Considerations... 7 Queue Analysis... 8 Crash History... 8 Benefit-Cost Analysis... 9 Summary and Recommendation Appendix A. Benefit/Cost Analysis Worksheets ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) ii

26 Background and Study Area As part of the Trunk Highway (TH) 22 Corridor Study, intersection control revisions are being considered at the intersection of TH 22 and Blue Earth County State Aid Highway 57/North Riverfront Drive (to be referred to as CSAH 57) just north of Mankato. The objective of this Intersection Control Evaluation report is to determine the optimal intersection that improves future traffic capacity and reduce crash potential. The following intersection control options were evaluated:» Two-way stop control (existing control)» Traffic signal» Continuous T-intersection» Single Lane Roundabout The study area can be seen in Figure 1. Roadway Characteristics TH 22 is functionally classified as a principal arterial and CSAH 57 is classified as a major collector. At the intersection, each roadway has a posted speed limit of 55 mph. The intersection is a four-legged intersection, with a private driveway to a single residence aligned with CSAH 57 being the east approach. Since this is a very low volume driveway, the intersection was evaluated as a T-intersection for intersection capacity analysis while considering the driveway access as a final consideration. STUDY INTERSECTION CONFIGURATION The intersection is currently stop controlled on the CSAH 57 approach. The lane configuration is:» Southbound: One through lane, dedicated right- and left-turn lanes» Northbound: Shared through/right-turn lane, dedicated left-turn lane» Eastbound: Shared through/left-turn lane, dedicated right-turn lane» Westbound: Driveway with no turn lanes ACCESS SPACING North of CSAH 57, the closest public access point is 238 th Street which is 2,800 feet (0.54 miles) away. South of CSAH 57, the closest public access point is 583 rd Avenue which is 3,450 feet (0.65 miles) away. These adjacent public access points are stop controlled on the minor approaches. MnDOT access spacing guidelines for rural principal arterials (Mn/DOT Access Management Manual [2008]) recommends 1-mile access spacing for primary full-movement intersections, and 1/2-mile access spacing for secondary intersections. Access and spacing recommendations are being developed with the TH 22 Corridor Study. Traffic Volumes Existing and projected average daily traffic volumes (ADT) and peak hour turning movements at the study intersection can be seen in Figure 1. Existing volumes are 2017 traffic volumes that were collected for the TH 22 Corridor Study. Based on discussions with the TH 22 corridor study Technical Advisory Committee, it has been established that 2045 traffic projections documented in this report reflect an aggressive growth scenario. Traffic projections for 2045 were developed through a review of historic traffic patterns and land use changes in the area average annual growth rates and 2030 ADT estimates were calculated based on 2017 daily intersection counts and assumed 1.8 percent to the north, 2.6 percent to the south, and 2.5 percent to the west. As such, if less intense development occurs in the area than assumed for the 2045 traffic projections, 2030 traffic projections presented in this document could approximate 2045 projections in a more moderate growth scenario. ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 1

27 Figure 1 Study Area Details ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 2

28 DIRECTIONAL TRAFFIC DISTRIBUTION Under AM peak hour conditions, a roughly even split between northbound and southbound vehicles is expected with both 2030 and 2045 traffic projections. A more unbalanced distribution is expected in the PM peak hour, with around 60 percent of traffic travelling northbound in both 2030 and MAJOR VERSUS MINOR VOLUMES Daily mainline volumes on TH 22 are expected to exceed minor approach volumes on CSAH 57 by an approximate sixto-one ratio in both 2030 and During the 2030 and 2045 AM peak hours, major approach volumes exceed minor approach left-turning movements by a ratio of around 17-to-one and 19-to-one, respectively. The PM peak hour ratio of major approach movements to minor approach left-turning movements is more balanced, but is around a sevento-one ratio in both 2030 and Warrant Analysis Traffic signal warrants from the Minnesota Manual on Uniform Traffic Control Devices were evaluated under existing and projected traffic volumes. Minor approach right-turns were omitted from this analysis given the presence of an eastbound right-turn lane on CSAH 57. Under existing traffic volumes Warrant 1b: Interruption of Continuous Traffic is met, and by 2030 Warrant 2: Four- Hour Vehicle Volume and Warrant 3: Peak Hour are also expected to be met. It is typical for a traffic signal or roundabout to be considered for MnDOT roadways when Warrant 1 is met (Scott Thompson MnDOT D7), which currently is met at the study intersection. By 2030, the volume threshold for Warrant 7: Crash Experience is met, however crash patterns (described more below) do not indicate a safety issue that would be mitigated with a traffic signal. Table 3 Signal Warrant Analysis (2017) Criteria Hours Met Hours Required Warrants Met Warrant 1a: Minimum Vehicular Volume 2 8 Not Met Warrant 1b: Interruption of Continuous Traffic 8 8 Met Warrant 2: Four-Hour Vehicular Volume 3 4 Not Met Warrant 3: Peak Hour 1 1 Met Warrant 7: Crash Experience 3* 8 Not Met Multi-way Stop Applications (MWSA) 0 8 Not Met *Hours meeting traffic volume component for Warrant 7 Table 4 Signal Warrant Analysis (2030) Criteria Hours Met Hours Required Warrants Met Warrant 1a: Minimum Vehicular Volume 5 8 Not Met Warrant 1b: Interruption of Continuous Traffic 12 8 Met Warrant 2: Four-Hour Vehicular Volume 10 4 Met Warrant 3: Peak Hour 4 1 Met Warrant 7: Crash Experience 11* 8 Met Check Crash History Multi-way Stop Applications (MWSA) 3 8 Not Met *Hours meeting traffic volume component for Warrant 7 ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 3

29 Traffic Operations Intersection level of service was evaluated for existing and future traffic conditions under each considered traffic control option. For two-way stop control and signal control, the Synchro 9/Simtraffic software was used and for roundabout control the HCS7 software was used. Each of these implement a level of service analysis methodology based on the Highway Capacity Manual methodology. Per MnDOT Access Management Manual and FHWA guidance, LOS E or worse will be considered an operational deficiency where mitigation should be discussed. Control delay thresholds for each level of service can be seen in Table 1. Table 1 Highway Capacity Manual Intersection Level of Service Thresholds Control Delay Unsignalized Signalized Level of Service (LOS) A > > B > > C > > D > > E > 50 > 80 F No Build: Two-Way Stop Control Under existing conditions, approach LOS B or better is expected on the eastbound approach. The minor approach is expected to operate at LOS F by 2030, with delays becoming so high (over 600 seconds per vehicle) that overall intersection LOS F is expected by Note: Delay presented in terms of seconds per vehicle Table 2 Two-Way Stop Control Delay and Level of Service Year AM Peak PM Peak NB SB EB Total NB SB EB Total A 4 A 9 A 4 A 2 A 4 A 15 B 5 A A 4 A 11 B 3 A 3 A 3 A 69 F 14 B A 5 A 23 C 5 A 4 A 3 A 667 F 101 F Under signal control, the intersection is expected to operate at intersection LOS B through 2045, with all approaches operating at LOS C or better. Note: Delay presented in terms of seconds per vehicle Table 3 Signal Control Delay and Level of Service Year AM Peak PM Peak NB SB EB Total NB SB EB Total A 7 A 11 B 7 A 9 A 9 A 19 B 11 B A 8 A 13 B 8 A 14 B 11 B 22 C 14 B Continuous T Intersection A continuous T intersection is a variant of the continuous green T intersection except it is unsignalized. This would add a dedicated receiving/acceleration lane for eastbound left-turns, which then merges with the northbound through lane downstream of the intersection. For modelling purposes, a 1,000 foot acceleration lane was assumed based on guidance in the AASHTO Policy on Geometric Design of Highways and Streets. ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 4

30 A continuous T intersection is expected to operate with minor approach LOS B or better under 2030 conditions and LOS C under 2040 conditions. Note: Delay presented in terms of seconds per vehicle PRIVATE ACCESS IMPACTS Table 4 Continuous T Intersection Control Delay and Level of Service Year AM Peak PM Peak NB SB EB Total NB SB EB Total A 1 A 8 A 2 A 2 A 1 A 12 B 3 A A 2 A 12 B 3 A 2 A 1 A 23 C 5 A Conversion to a continuous T intersection would require the relocation of the private access that makes up the fourth leg of the intersection. Given the proximity to 583 rd Avenue, access could potentially be relocated to this roadway. Figure 2 Private Access Impacts with Continuous T Intersection Private Access 583 rd Ave CSAH 57 ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 5

31 Figure 3 Continuous T Intersection Configuration North ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 6

32 Roundabout Control Roundabout level of service was calculated using the HCS 7 software, which implements the roundabout capacity analysis methodology from the sixth edition of the Highway Capacity Manual. The assumed lane geometry for a roundabout is shown in Figure 4. A single lane was assumed on all approaches except the southbound approach, where a right-turn bypass lane was assumed. Figure 4 Assumed Roundabout Geometry Under roundabout control, intersection LOS A is expected through Through 2045, intersection LOS C or better is expected, with the lowest approach level of service being northbound LOS C during the 2045 PM peak hour. Note: Delay presented in terms of seconds per vehicle TRUCK CONSIDERATIONS Table 5 Roundabout Delay and Level of Service Year AM Peak PM Peak NB SB EB Total NB SB EB Total A 7 A 7 A 7 A 13 B 6 A 9 A 9 A B 8 A 9 A 9 A 24 C 8 A 12 B 16 C Roundabouts have been successfully constructed on many Minnesota trunk highways, including two on the TH 22 corridor in Mankato. With proper roundabout design characteristics such as a sufficient inscribed circle diameter and truck aprons with curbs designed to prevent load shifting, trucks can navigate roundabouts without issue. MnDOT roundabout design guidelines recommend an inscribed circle diameter of 120 feet to 150 feet for single lane rural roundabouts (MnDOT Road Design Manual Table A [2009]), and information from MnDOT s Rightof-Way Mapping and Monitoring web application indicates available right-of-way for such design. ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 7

33 Queue Analysis A review of 95 th percentile queue indicates that significant queueing is expected on the minor approach under twoway stop control, with the 2045 PM peak queue exceeding 500 feet in length. If converted to a signalized intersection or continuous T intersection, queue lengths are expected to significantly improve compared to two-way stop control, with no queues exceeding existing storage lengths through Longer queues are expected on TH 22 under roundabout control than signal control or a continuous T configuration, with the longest expected 2045 queue under roundabout control being a 280 foot queue on the northbound approach in the PM peak hour. Approach Direction Table 6 95 th Percentile Queues Crash History Crash data was obtained from MnDOT for the time period between January 2011 and December In the fiveyear period, seven crashes were reported. Six run-off-the-road crashes and one other non-specified crash were reported. Two crashes resulted in non-incapacitating injuries. Four of six run-off-the-road crashes occurred when it was dark outside, which could be attributable to the horizontal roadway curvature just north of the intersection. Using the critical crash analysis methodology which applies statistical analysis to determine if the difference in observed and typical crash rates is statistically significant, the intersection crash rate is not above the critical crash rate but is above the statewide average. Based on research-supported crash modification factors, the following safety impacts are expected from traffic control revisions:» Signal Control 2030 AM 2030 PM 2045 AM Total crash reduction of 44 percent Angle crash reduction of 77 percent Left-turn crash reduction of 60 percent Rear-end crash increase of 58 percent o Source: Harkey, et al. National Cooperative Highway Research Report 617: Accident Modification Factors for Traffic Engineering and ITS Improvements (2008)» Signalized Continuous T Intersection 2045 PM 2030 AM Traffic Signal PM AM 2045 PM Total crash reduction of 60 percent Injury crash reduction of 70 percent Angle crash reduction of 97 percent o FHWA case study FHWA-SA (2010) 2030 AM Continuous T PM AM 2045 PM 2030 AM Roundabout PM AM Left Northbound Thru Southbound Existing Storage No Build Thru Right Left Eastbound Right PM ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 8

34 » Roundabout control Total crash reduction of 71 percent Injury crash reduction of 82 percent o Rodegerdts, et al. National Cooperative Highway Research Report 572: Applying Roundabouts in the United States (2007) While data was only available for a signalized continuous green T intersection, minor approach left-turning unsignalized movements would simplify gap acceptance since drivers would not have to evaluate gap acceptability for northbound through vehicles. Roundabout control is expected to significantly reduce overall crash potential, especially for injury crashes due to eliminating high-speed angle crash potential. Run-off-the-road crashes were the most common crash type at the intersection, and a properly designed and signed roundabout with expanded roadway lighting (lighting only currently exists at the intersection) could potentially reduce this crash type by slowing vehicle speeds near the roadway curvature on the north intersection approach. Benefit-Cost Analysis Benefit-Cost Analysis (BCA) provides an indication of the economic desirability of an alternative, by comparing the benefits along with the assessment of other effects and impacts. Projects are considered cost-effective if the benefitcost ratio is greater than 1.0. The larger the ratio number, the greater the benefits per unit cost. A BCA was performed for the three intersection alternatives compared to the existing two-way stop intersection. The analysis was based on MnDOT Benefit-Cost Analysis Guidelines (SFY2019) to compare to similar projects throughout the region. Vehicle miles traveled (VMT), vehicle hours traveled (VHT), and crash reduction savings were quantified to evaluate operational and safety benefits. Construction costs, maintenance costs, and remaining capitol value were quantified to represent the total user costs for the project. The benefits and costs of each alternative were compared for a 20-year timeframe assumed between Based on the actual construction year, these results may increase or decrease slightly from the assumptions used for the current analysis. For the purposes of this ICE report, economic desirability of the concept was compared between intersection alternatives. Table 7 shows a summary of the BCA results for traffic signal, roundabout, and continuous T alternatives. Both the Traffic Signal and Continuous T alternatives provide an economic improvement to the intersection with the Continuous T providing over four times the benefit of a traffic signal but also being four times the cost. Although the roundabout alternative had a high safety benefit, the reduction of speed along an existing two-lane highway caused a negative net benefit due to traffic operations. Table 7 20 Year BCA Analysis Results Traffic Signal Roundabout Continuous T Net Cost of Project ($M) $0.22 $0.74 $1.13 Present Value of Benefits ($M) $0.84 -$0.09 $4.03 Net Present Value ($M) $0.62 -$0.84 $2.90 Benefit / Cost Ratio ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 9

35 Summary and Recommendation The existing two-way stop control is expected to result in deficient operations on the eastbound approach by A traffic signal, continuous T intersection, or a roundabout are all expected to improve intersection operations, all providing LOS C or better. Multimodal operations are expected to be similar under each scenario due to the rural nature of the intersection. A trail on the east side of TH 22 would have significantly lower vehicle crossing volumes than a trail on the west side. From a safety perspective, a traffic signal would reduce angle crash potential, but has the potential to increase rearend crash potential, especially given the rural high-speed design of TH 22 at the intersection. A roundabout is expected to provide the greatest safety benefit, especially for run-off-the-road crashes (most common crash type at this location), but the imbalanced major-to-minor approach volume ratios could result in rear-end crash potential on TH 22. A continuous T intersection is expected to have significant safety and operational improvements, but it is important to note that available safety data is for a signalized continuous T intersection rather than a stop-controlled configuration. A traffic signal is not recommended at this time due to the rural roadway characteristics and associated rear-end crash potential, and acceptable operations can be provided with a continuous T intersection or roundabout. The economic desirability of a Continuous T far outweighs that of a roundabout even with a higher price tag. This is due to allowing TH 22 through traffic to be free from intersection delay caused by the traffic signal and roundabout control types. A Continuous T design also allows the ability to signalize the design in the future for additional capacity for CSAH 57 movements. Given the highest benefits (and high BCA ratio) with a continuous T intersection compared to a roundabout (see Table 8) as well as the similar expected safety benefits, a continuous T is recommended at CSAH 57. It is also recommended that traffic operations and safety are monitored, with conversion to a signalized continuous T or a roundabout being a potential long-term solution if side street volumes continue to increase as the TH 22 corridor continues to build out toward CSAH 57. ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 10

36 Table 8 Summary of Analysis Alternative Do Nothing (TWSC) Lane Configuration Alternative Assessment TH 22 and Blue Earth CSAH 57 Traffic Operations Year Peak LOS* Existing AM PM AM PM AM PM A B C E C F Safety Assessment Crash rate above statewide average 7 crashes in 5 years (2 injury crashes) 6 run-off-the-road crashes No Expected Change in Crash Patterns Without Traffic Control Revisions Preliminary Cost Estimate $0 Traffic Signal AM PM AM PM A B A B Total Crash Reduction of 44% Angle Crash Reduction of 77% Left-Turn Crash Reduction of 60% Rear-End Crash Increase of 58% $250 - $450 K Continuous T Intersection (Stop Control) Merge AM PM AM PM A B A C Total Crash Reduction of 60% Injury crash reduction of 70% Angle crash reduction of 97% Note: Available safety assumes signal controlled continuous T configuration $1.5 - $1.7 M Roundabout AM PM AM PM A A A C Total Crash Reduction of 71% Injury Crash Reduction of 82% $1.0 - $1.2 M *Lowest approach LOS for TWSC and continuous T, overall intersection LOS for traffic signal and roundabout ICE Report TH 22 and Blue Earth CSAH 57 (North Riverfront Drive) 11

37 Appendix A Benefit/Cost Analysis Worksheets

38 Benefit Cost Analysis Workbook Project Name: TH 22 Corridor Study Alternative: CSAH 57 Continuous T BCA Base Year: 2021 Summary of Results Net Cost of Project ($M) Present Value of Benefits ($M) Net Present Value ($M) Weekday $1.13 $4.03 $2.90 BCA Future Year: 2040 Benefit / Cost Ratio: 3.55 Year PRESENT VALUE OF USER BENEFITS VHTBenefits VMT Benefits Crash Reduction Savings Present Value of Total User Benefits ($) PRESENT VALUE OF USER Costs Construction Costs Maintenance Costs Remaining Capital Value Present Value of Total User Costs ($) $1,630,435 $0 $0 $ 1,630, $53,231 $26,960 $52,020 $ 132, $60,526 $26,953 $53,254 $ 140, $67,640 $26,942 $54,452 $ 149, $74,577 $26,928 $55,614 $ 157, $81,340 $26,910 $56,741 $ 164, $87,932 $26,889 $57,833 $ 172, $94,357 $26,864 $58,891 $ 180, $100,616 $26,837 $59,916 $ 187, $106,714 $26,806 $60,909 $ 194, $112,654 $26,772 $61,869 $ 201, $118,437 $26,735 $62,798 $ 207, $124,067 $26,695 $63,697 $ 214, $129,547 $26,653 $64,565 $ 220, $134,880 $26,608 $65,404 $ 226, $140,068 $26,560 $66,214 $ 232, $145,114 $26,509 $66,995 $ 238, $150,021 $26,456 $67,748 $ 244, $154,791 $26,400 $68,475 $ 249, $159,427 $26,342 $69,174 $ 254, $163,931 $26,282 $69,847 $ 260,060 $0 $0 -$496,627 $ (496,627) Total for Project Life $2,259,871 $534,100 $1,236,418 $4,030,389 $1,630,435 $0 -$496,627 $1,133,808 BCA Workbook CSAH 57 Green T Page 1 of 5

39 Benefit Cost Analysis Workbook Project Name: TH 22 Corridor Study Alternative CSAH 57 Continuous T BCA Base Year: 2021 BCA Future Year: 2040 ANALYSIS TIMEFRAME Years of Construction Base Build First Year of Construction Duration of Construction 1 1 Length of B/C Analysis Period 20 years Benefit-cost First Year of Benefit: 2021 Benefit-cost Final Year of Analysis/Year of Remaining Capital Value: 2040 Length of Traffic Analysis Period 13 years First Year of Traffic Analysis: 2018 Final Year of Traffic Analysis: 2030 Intersection/Corridor AADT Base Build Existing AADT 11,300 11,300 Future AADT 16,775 16,775 NETWORK ASSUMPTIONS Truck Percentage Base Build Percent Autos 95.2% 95.2% Percent Trucks 4.8% 4.8% Average Vehicle Occupancy Ratios Base Build Automobile Truck Traffic - Daily VMT and VHT Base Build Year 1 Daily Vehicle Miles Traveled (VMT) ,369 2,181 Year 13 Daily Vehicle Miles Traveled (VMT) ,205 2,989 Year 1 Daily Vehicle Hours Traveled (VHT) Year 13 Daily Vehicle Hours Traveled (VHT) GLOBAL ASSUMPTIONS AND FACTORS General Economic Parameters Year of Analysis 2018 Number of Days in a Year (Assumed) 260 Real Discount Rate 1.2% Costs per Hour Value Units Automobile $18.90 $/hr Truck $30.30 $/hr Costs per Mile Value Units Automobile $0.32 $/mile Truck $0.99 $/mile Composite Cost per Hour $31.02 $/hr Composite Cost per Mile $0.55 $/mile MnDOT Crash Costs Value # of Crashes Fatal $11,100,000 0 Injury Type A $600,000 0 Injury Type B $180,000 2 Injury Type C $87,000 0 Property damage only $7,200 5 Build Crash Reduction % Build Crash Reduction % BCA Workbook CSAH 57 Green T Page 2 of 5

40 Benefit Cost Analysis Workbook Remaining Capital Value Maintenance Costs Preliminary Engineering Right of Way Major Structures Removal Grading and Drainage Sub-Base and Base Surface Base Build Base Cost Remaining Useful Remaining Useful Total Roadway Length Annual Maintenance Life (Yr) Build Cost Life (Yr) Roadway Facility (lane-mi) Cost Per Lane-Mi ($) Total ($) $0 0% $310,000 0% Trunk Highway 1.0 $ 10, $ 10, $0 80% $100,000 80% CSAH 1.0 $ 8, $ 8, $0 67% $0 67% $ - Base $0 0% $0 0% $0 60% $310,000 60% Annual Maintenance Costs: $ 18, $0 50% $620,000 50% Total Roadway Length Annual Maintenance New Roadway Facility $0 20% $310,000 20% (lane-mi) Cost Per Lane-Mi ($) Total ($) $0 $1,550,000 Trunk Highway 1.0 $ 10, $ 10, $0 $0 Frontage Road 1.0 $ 8, $ 8, $1,650,000 $638,000 $ - Annual Maintenance Costs: $ 18, Build Construction Calculations Year Present Value of Capital Cost Present Value of Maintenance Cost Base Build Base Build Present Value of Remaining Capital Value Present Value of Net Annual Costs ($) $0 $0 $0 $0 $0 $0 $ $0 $1,630,435 $0 $0 $0 $0 $1,630, $0 $0 $18,064 $18,064 $0 $0 $ $0 $0 $17,850 $17,850 $0 $0 $ $0 $0 $17,638 $17,638 $0 $0 $ $0 $0 $17,429 $17,429 $0 $0 $ $0 $0 $17,222 $17,222 $0 $0 $ $0 $0 $17,018 $17,018 $0 $0 $ $0 $0 $16,816 $16,816 $0 $0 $ $0 $0 $16,617 $16,617 $0 $0 $ $0 $0 $16,420 $16,420 $0 $0 $ $0 $0 $16,225 $16,225 $0 $0 $ $0 $0 $16,033 $16,033 $0 $0 $ $0 $0 $15,843 $15,843 $0 $0 $ $0 $0 $15,655 $15,655 $0 $0 $ $0 $0 $15,469 $15,469 $0 $0 $ $0 $0 $15,286 $15,286 $0 $0 $ $0 $0 $15,104 $15,104 $0 $0 $ $0 $0 $14,925 $14,925 $0 $0 $ $0 $0 $14,748 $14,748 $0 $0 $ $0 $0 $14,573 $14,573 $0 $0 $ $0 $0 $14,401 $14,401 $0 $496,627 -$496,627 Total Project Life Benefit $0 $1,630,435 $323,335 $323,335 $0 $496,627 $1,133,808 Base Build BCA Workbook CSAH 57 Green T Page 3 of 5

41 Benefit Cost Analysis Workbook VHT Calcs VMT Calcs First year of traffic analysis $38,087 $38,087 First year of benefitcost analysis Year First year of traffic analysis , ,944 49,111 $26,963 $26, $46,301 $45, , ,458 49,701 $27,287 $26, $54,516 $53,231 First year of benefitcost analysis , ,972 50,291 $27,611 $26, $62,731 $60, , ,486 50,881 $27,935 $26, $70,946 $67, , ,000 51,470 $28,259 $26, $79,160 $74, , ,514 52,060 $28,583 $26, $87,375 $81, , ,028 52,650 $28,906 $26, $95,590 $87, , ,542 53,240 $29,230 $26, $103,805 $94, , ,056 53,830 $29,554 $26, $112,019 $100, , ,569 54,419 $29,878 $26, $120,234 $106, , ,083 55,009 $30,202 $26, $128,449 $112, , ,597 55,599 $30,526 $26, $136,664 $118, , ,111 56,189 $30,849 $26, $144,878 $124, , ,625 56,779 $31,173 $26, $153,093 $129, , ,139 57,369 $31,497 $26, $161,308 $134, , ,653 57,958 $31,821 $26, $169,523 $140, , ,167 58,548 $32,145 $26, $177,738 $145, , ,681 59,138 $32,469 $26, $185,952 $150, , ,194 59,728 $32,792 $26,456 Last year of traffic analysis $194,167 $154,791 Last year of benefitcost analysis 2039 Base (hrs) VHT Build (hrs) Last year of traffic analysis , ,708 60,318 $33,116 $26, $202,382 $159, , ,222 60,907 $33,440 $26, $210,597 $163,931 Total Project Life Benefit Benefit (hrs) Constant Benefit ($) Present Value of Savings ($) Year Last year of benefitcost analysis 2039 Base (miles) Build (miles) Benefit (miles) 996, ,736 61,497 $33,764 $26, $2,651,127 $2,259,871 Total Project Life Benefit 1,117,880 $613,750 $534,100 VMT Constant Benefit ($) Present Value of Savings ($) BCA Workbook CSAH 57 Green T Page 4 of 5

42 Benefit Cost Analysis Workbook Crash Data Crash Analysis Crash Base Base Build Values Corridor AADT 11,300 11,300 16,775 16,775 ($ per crash) Reduction 60% 60% Fatal $ 11,100,000 Crash A $ 600,000 Severity B $ 180,000 (5 year C $ 87,000 data) PDO $ 7, $ 79, $ 31, $ 117, $ 47,029 Year Crash Calculations Base Build Annual Forecast Annual Forecast Number of Crashes Estimated Cost Number of Crashes Estimated Cost Constant Benefit ($) Present Value of Savings ($) First year of traffic analysis $82, $ 32,959 $ 49,439 $ 49, $85, $ 34,238 $ 51,357 $ 50,748 First year of benefitcost analysis $88, $ 35,517 $ 53,276 $ 52, $91, $ 36,796 $ 55,195 $ 53, $95, $ 38,076 $ 57,113 $ 54, $98, $ 39,355 $ 59,032 $ 55, $101, $ 40,634 $ 60,951 $ 56, $104, $ 41,913 $ 62,869 $ 57, $107, $ 43,192 $ 64,788 $ 58, $111, $ 44,471 $ 66,707 $ 59, $114, $ 45,750 $ 68,625 $ 60, $117, $ 47,029 $ 70,544 $ 61, $120, $ 48,308 $ 72,463 $ 62, $123, $ 49,588 $ 74,381 $ 63, $127, $ 50,867 $ 76,300 $ 64, $130, $ 52,146 $ 78,219 $ 65, $133, $ 53,425 $ 80,137 $ 66, $136, $ 54,704 $ 82,056 $ 66, $139, $ 55,983 $ 83,975 $ 67,748 Last year of traffic analysis $143, $ 57,262 $ 85,893 $ 68, $146, $ 58,541 $ 87,812 $ 69,174 Last year of benefitcost analysis $149, $ 59,821 $ 89,731 $ 69,847 Total Project Life Benefit $ 1,430,068 $ 1,236,418 BCA Workbook CSAH 57 Green T Page 5 of 5

43 Benefit Cost Analysis Workbook Project Name: TH 22 Corridor Study Alternative: CSAH 57 RAB BCA Base Year: 2021 BCA Future Year: 2040 Summary of Results Net Cost of Project ($M) Present Value of Benefits ($M) Net Present Value ($M) Benefit / Cost Ratio: Weekday $0.74 $0.09 $ Year PRESENT VALUE OF USER BENEFITS VHTBenefits VMT Benefits Crash Reduction Savings Present Value of Total User Benefits ($) PRESENT VALUE OF USER Costs Construction Costs Maintenance Costs Remaining Capital Value Present Value of Total User Costs ($) $1,086,957 $0 $0 $ 1,086, $94,066 $21,243 $61,557 $ (11,266) $95,112 $21,616 $63,018 $ (10,478) $96,120 $21,977 $64,435 $ (9,708) $97,091 $22,327 $65,810 $ (8,954) $98,025 $22,665 $67,143 $ (8,217) $98,924 $22,992 $68,436 $ (7,496) $99,787 $23,308 $69,688 $ (6,791) $100,616 $23,613 $70,901 $ (6,102) $101,412 $23,908 $72,075 $ (5,428) $102,174 $24,193 $73,212 $ (4,770) $102,904 $24,467 $74,311 $ (4,126) $103,603 $24,732 $75,375 $ (3,496) $104,270 $24,986 $76,402 $ (2,882) $104,907 $25,232 $77,395 $ (2,281) $105,514 $25,468 $78,353 $ (1,694) $106,092 $25,694 $79,277 $ (1,120) $106,641 $25,912 $80,169 $ (560) $107,163 $26,121 $81,028 $ (13) $107,657 $26,322 $81,856 $ $108,125 $26,514 $82,653 $ 1,042 $0 $0 -$342,501 $ (342,501) Total for Project Life -$2,040,203 $483,288 $1,463,095 -$93,820 $1,086,957 $0 -$342,501 $744,455 BCA Workbook CSAH 57 RAB Page 1 of 5

44 Benefit Cost Analysis Workbook Project Name: TH 22 Corridor Study Alternative CSAH 57 RAB BCA Base Year: 2021 BCA Future Year: 2040 ANALYSIS TIMEFRAME Years of Construction Base Build First Year of Construction Duration of Construction 1 1 Length of B/C Analysis Period 20 years Benefit-cost First Year of Benefit: 2021 Benefit-cost Final Year of Analysis/Year of Remaining Capital Value: 2040 Length of Traffic Analysis Period 13 years First Year of Traffic Analysis: 2018 Final Year of Traffic Analysis: 2030 Intersection/Corridor AADT Base Build Existing AADT 11,300 11,300 Future AADT 16,775 16,775 NETWORK ASSUMPTIONS Truck Percentage Base Build Percent Autos 95.2% 95.2% Percent Trucks 4.8% 4.8% Average Vehicle Occupancy Ratios Base Build Automobile Truck Traffic - Daily VMT and VHT Base Build Year 1 Daily Vehicle Miles Traveled (VMT) ,369 2,226 Year 13 Daily Vehicle Miles Traveled (VMT) ,205 3,007 Year 1 Daily Vehicle Hours Traveled (VHT) Year 13 Daily Vehicle Hours Traveled (VHT) GLOBAL ASSUMPTIONS AND FACTORS General Economic Parameters Year of Analysis 2018 Number of Days in a Year (Assumed) 260 Real Discount Rate 1.2% Costs per Hour Value Units Automobile $18.90 $/hr Truck $30.30 $/hr Costs per Mile Value Units Automobile $0.32 $/mile Truck $0.99 $/mile Composite Cost per Hour $31.02 $/hr Composite Cost per Mile $0.55 $/mile MnDOT Crash Costs Value # of Crashes Fatal $11,100,000 0 Injury Type A $600,000 0 Injury Type B $180,000 2 Injury Type C $87,000 0 Property damage only $7,200 5 Build Crash Reduction % Build Crash Reduction % BCA Workbook CSAH 57 RAB Page 2 of 5

45 Benefit Cost Analysis Workbook Remaining Capital Value Maintenance Costs Preliminary Engineering Right of Way Major Structures Removal Grading and Drainage Sub-Base and Base Surface Base Build Base Cost Remaining Useful Remaining Useful Total Roadway Length Annual Maintenance Life (Yr) Build Cost Life (Yr) Roadway Facility (lane-mi) Cost Per Lane-Mi ($) Total ($) $0 0% $200,000 0% Trunk Highway 1.0 $ 10, $ 10, $0 80% $100,000 80% CSAH 1.0 $ 8, $ 8, $0 67% $0 67% $ - Base $0 0% $0 0% $0 60% $200,000 60% Annual Maintenance Costs: $ 18, $0 50% $400,000 50% Total Roadway Length Annual Maintenance New Roadway Facility $0 20% $200,000 20% (lane-mi) Cost Per Lane-Mi ($) Total ($) $0 $1,000,000 Trunk Highway 1.0 $ 10, $ 10, $0 $0 Frontage Road 1.0 $ 8, $ 8, $1,100,000 $440,000 $ - Annual Maintenance Costs: $ 18, Build Construction Calculations Year Present Value of Capital Cost Present Value of Maintenance Cost Base Build Base Build Present Value of Remaining Capital Value Present Value of Net Annual Costs ($) $0 $0 $0 $0 $0 $0 $ $0 $1,086,957 $0 $0 $0 $0 $1,086, $0 $0 $18,064 $18,064 $0 $0 $ $0 $0 $17,850 $17,850 $0 $0 $ $0 $0 $17,638 $17,638 $0 $0 $ $0 $0 $17,429 $17,429 $0 $0 $ $0 $0 $17,222 $17,222 $0 $0 $ $0 $0 $17,018 $17,018 $0 $0 $ $0 $0 $16,816 $16,816 $0 $0 $ $0 $0 $16,617 $16,617 $0 $0 $ $0 $0 $16,420 $16,420 $0 $0 $ $0 $0 $16,225 $16,225 $0 $0 $ $0 $0 $16,033 $16,033 $0 $0 $ $0 $0 $15,843 $15,843 $0 $0 $ $0 $0 $15,655 $15,655 $0 $0 $ $0 $0 $15,469 $15,469 $0 $0 $ $0 $0 $15,286 $15,286 $0 $0 $ $0 $0 $15,104 $15,104 $0 $0 $ $0 $0 $14,925 $14,925 $0 $0 $ $0 $0 $14,748 $14,748 $0 $0 $ $0 $0 $14,573 $14,573 $0 $0 $ $0 $0 $14,401 $14,401 $0 $342,501 -$342,501 Total Project Life Benefit $0 $1,086,957 $323,335 $323,335 $0 $342,501 $744,455 Base Build BCA Workbook CSAH 57 RAB Page 3 of 5

46 Benefit Cost Analysis Workbook VHT Calcs VMT Calcs First year of traffic analysis $91,856 -$91,856 First year of benefitcost analysis Year First year of traffic analysis , ,789 37,267 $20,461 $20, $94,096 -$92, , ,713 38,446 $21,108 $20, $96,337 -$94,066 First year of benefitcost analysis , ,637 39,626 $21,756 $21, $98,577 -$95, , ,561 40,806 $22,403 $21, $100,817 -$96, , ,485 41,985 $23,051 $21, $103,058 -$97, , ,409 43,165 $23,699 $22, $105,298 -$98, , ,333 44,344 $24,346 $22, $107,539 -$98, , ,257 45,524 $24,994 $22, $109,779 -$99, , ,181 46,704 $25,642 $23, $112,019 -$100, , ,106 47,883 $26,289 $23, $114,260 -$101, , ,030 49,063 $26,937 $23, $116,500 -$102, , ,954 50,243 $27,585 $24, $118,741 -$102, , ,878 51,422 $28,232 $24, $120,981 -$103, , ,802 52,602 $28,880 $24, $123,221 -$104, , ,726 53,781 $29,528 $24, $125,462 -$104, , ,650 54,961 $30,175 $25, $127,702 -$105, , ,574 56,141 $30,823 $25, $129,943 -$106, , ,498 57,320 $31,471 $25, $132,183 -$106, , ,422 58,500 $32,118 $25,912 Last year of traffic analysis $134,423 -$107,163 Last year of benefitcost analysis 2039 Base (hrs) VHT Build (hrs) Last year of traffic analysis , ,346 59,680 $32,766 $26, $136,664 -$107, , ,270 60,859 $33,414 $26, $138,904 -$108,125 Total Project Life Benefit Benefit (hrs) Constant Benefit ($) Present Value of Savings ($) Year Last year of benefitcost analysis 2039 Base (miles) Build (miles) Benefit (miles) 996, ,194 62,039 $34,061 $26, $2,352,408 -$2,040,203 Total Project Life Benefit 1,016,648 $558,171 $483,288 VMT Constant Benefit ($) Present Value of Savings ($) BCA Workbook CSAH 57 RAB Page 4 of 5

47 Benefit Cost Analysis Workbook Crash Data Crash Analysis Crash Base Base Build Values Corridor AADT 11,300 11,300 16,775 16,775 ($ per crash) Reduction 71% 71% Fatal $ 11,100,000 Crash A $ 600,000 Severity B $ 180,000 (5 year C $ 87,000 data) PDO $ 7, $ 79, $ 22, $ 117, $ 34,096 Year Crash Calculations Base Build Annual Forecast Annual Forecast Number of Crashes Estimated Cost Number of Crashes Estimated Cost Constant Benefit ($) Present Value of Savings ($) First year of traffic analysis $82, $ 23,895 $ 58,502 $ 58, $85, $ 24,823 $ 60,773 $ 60,052 First year of benefitcost analysis $88, $ 25,750 $ 63,043 $ 61, $91, $ 26,677 $ 65,314 $ 63, $95, $ 27,605 $ 67,584 $ 64, $98, $ 28,532 $ 69,855 $ 65, $101, $ 29,460 $ 72,125 $ 67, $104, $ 30,387 $ 74,395 $ 68, $107, $ 31,314 $ 76,666 $ 69, $111, $ 32,242 $ 78,936 $ 70, $114, $ 33,169 $ 81,207 $ 72, $117, $ 34,096 $ 83,477 $ 73, $120, $ 35,024 $ 85,748 $ 74, $123, $ 35,951 $ 88,018 $ 75, $127, $ 36,878 $ 90,288 $ 76, $130, $ 37,806 $ 92,559 $ 77, $133, $ 38,733 $ 94,829 $ 78, $136, $ 39,660 $ 97,100 $ 79, $139, $ 40,588 $ 99,370 $ 80,169 Last year of traffic analysis $143, $ 41,515 $ 101,641 $ 81, $146, $ 42,443 $ 103,911 $ 81,856 Last year of benefitcost analysis $149, $ 43,370 $ 106,181 $ 82,653 Total Project Life Benefit $ 1,692,247 $ 1,463,095 BCA Workbook CSAH 57 RAB Page 5 of 5

48 Benefit Cost Analysis Workbook Project Name: TH 22 Corridor Study Alternative: CSAH 57 Traffic Signal BCA Base Year: 2021 Summary of Results Net Cost of Project ($M) Present Value of Benefits ($M) Net Present Value ($M) Weekday $0.22 $0.84 $0.62 BCA Future Year: 2040 Benefit / Cost Ratio: 3.78 Year PRESENT VALUE OF USER BENEFITS VHTBenefits VMT Benefits Crash Reduction Savings Present Value of Total User Benefits ($) PRESENT VALUE OF USER Costs Construction Costs Maintenance Costs Remaining Capital Value Present Value of Total User Costs ($) $326,087 $0 $0 $ 326, $41,928 $168 $38,148 $ (3,613) $37,288 $172 $39,053 $ 1, $32,752 $176 $39,932 $ 7, $28,318 $181 $40,784 $ 12, $23,985 $185 $41,610 $ 17, $19,750 $188 $42,411 $ 22, $15,613 $192 $43,187 $ 27, $11,571 $196 $43,939 $ 32, $7,622 $199 $44,666 $ 37, $3,766 $203 $45,371 $ 41, $0 $206 $46,052 $ 46, $3,677 $209 $46,711 $ 50, $7,267 $213 $47,348 $ 54, $10,772 $216 $47,963 $ 58, $14,192 $218 $48,557 $ 62, $17,530 $221 $49,130 $ 66, $20,786 $224 $49,682 $ 70, $23,963 $227 $50,215 $ 74, $27,061 $229 $50,728 $ 78, $30,083 $231 $51,221 $ 81,536 $0 $0 -$102,750 $ (102,750) Total for Project Life -$67,263 $4,055 $906,706 $843,498 $326,087 $0 -$102,750 $223,337 BCA Workbook CSAH 57 Signal Page 1 of 5

49 Benefit Cost Analysis Workbook Project Name: TH 22 Corridor Study Alternative CSAH 57 Traffic Signal BCA Base Year: 2021 BCA Future Year: 2040 ANALYSIS TIMEFRAME Years of Construction Base Build First Year of Construction Duration of Construction 1 1 Length of B/C Analysis Period 20 years Benefit-cost First Year of Benefit: 2021 Benefit-cost Final Year of Analysis/Year of Remaining Capital Value: 2040 Length of Traffic Analysis Period 13 years First Year of Traffic Analysis: 2018 Final Year of Traffic Analysis: 2030 Intersection/Corridor AADT Base Build Existing AADT 11,300 11,300 Future AADT 16,775 16,775 NETWORK ASSUMPTIONS Truck Percentage Base Build Percent Autos 95.2% 95.2% Percent Trucks 4.8% 4.8% Average Vehicle Occupancy Ratios Base Build Automobile Truck Traffic - Daily VMT and VHT Base Build Year 1 Daily Vehicle Miles Traveled (VMT) ,369 2,368 Year 13 Daily Vehicle Miles Traveled (VMT) ,205 3,203 Year 1 Daily Vehicle Hours Traveled (VHT) Year 13 Daily Vehicle Hours Traveled (VHT) GLOBAL ASSUMPTIONS AND FACTORS General Economic Parameters Year of Analysis 2018 Number of Days in a Year (Assumed) 260 Real Discount Rate 1.2% Costs per Hour Value Units Automobile $18.90 $/hr Truck $30.30 $/hr Costs per Mile Value Units Automobile $0.32 $/mile Truck $0.99 $/mile Composite Cost per Hour $31.02 $/hr Composite Cost per Mile $0.55 $/mile MnDOT Crash Costs Value # of Crashes Fatal $11,100,000 0 Injury Type A $600,000 0 Injury Type B $180,000 2 Injury Type C $87,000 0 Property damage only $7,200 5 Build Crash Reduction % Build Crash Reduction % BCA Workbook CSAH 57 Signal Page 2 of 5

50 Benefit Cost Analysis Workbook Remaining Capital Value Maintenance Costs Preliminary Engineering Right of Way Major Structures Removal Grading and Drainage Sub-Base and Base Surface Base Build Base Cost Remaining Useful Remaining Useful Total Roadway Length Annual Maintenance Life (Yr) Build Cost Life (Yr) Roadway Facility (lane-mi) Cost Per Lane-Mi ($) Total ($) $0 0% $60,000 0% Trunk Highway 1.0 $ 10, $ 10, $0 80% $30,000 80% CSAH 1.0 $ 8, $ 8, $0 67% $0 67% $ - Base $0 0% $0 0% $0 60% $60,000 60% Annual Maintenance Costs: $ 18, $0 50% $120,000 50% Total Roadway Length Annual Maintenance New Roadway Facility $0 20% $60,000 20% (lane-mi) Cost Per Lane-Mi ($) Total ($) $0 $300,000 Trunk Highway 1.0 $ 10, $ 10, $0 $0 Frontage Road 1.0 $ 8, $ 8, $330,000 $132,000 $ - Annual Maintenance Costs: $ 18, Build Construction Calculations Year Present Value of Capital Cost Present Value of Maintenance Cost Base Build Base Build Present Value of Remaining Capital Value Present Value of Net Annual Costs ($) $0 $0 $0 $0 $0 $0 $ $0 $326,087 $0 $0 $0 $0 $326, $0 $0 $18,064 $18,064 $0 $0 $ $0 $0 $17,850 $17,850 $0 $0 $ $0 $0 $17,638 $17,638 $0 $0 $ $0 $0 $17,429 $17,429 $0 $0 $ $0 $0 $17,222 $17,222 $0 $0 $ $0 $0 $17,018 $17,018 $0 $0 $ $0 $0 $16,816 $16,816 $0 $0 $ $0 $0 $16,617 $16,617 $0 $0 $ $0 $0 $16,420 $16,420 $0 $0 $ $0 $0 $16,225 $16,225 $0 $0 $ $0 $0 $16,033 $16,033 $0 $0 $ $0 $0 $15,843 $15,843 $0 $0 $ $0 $0 $15,655 $15,655 $0 $0 $ $0 $0 $15,469 $15,469 $0 $0 $ $0 $0 $15,286 $15,286 $0 $0 $ $0 $0 $15,104 $15,104 $0 $0 $ $0 $0 $14,925 $14,925 $0 $0 $ $0 $0 $14,748 $14,748 $0 $0 $ $0 $0 $14,573 $14,573 $0 $0 $ $0 $0 $14,401 $14,401 $0 $102,750 -$102,750 Total Project Life Benefit $0 $326,087 $323,335 $323,335 $0 $102,750 $223,337 Base Build BCA Workbook CSAH 57 Signal Page 3 of 5

51 Benefit Cost Analysis Workbook VHT Calcs VMT Calcs First year of traffic analysis $51,529 -$51,529 First year of benefitcost analysis Year First year of traffic analysis , , $159 $ $47,235 -$46, , , $165 $ $42,941 -$41,928 First year of benefitcost analysis , , $172 $ $38,647 -$37, , , $178 $ $34,353 -$32, , , $185 $ $30,059 -$28, , , $192 $ $25,764 -$23, , , $198 $ $21,470 -$19, , , $205 $ $17,176 -$15, , , $211 $ $12,882 -$11, , , $218 $ $8,588 -$7, , , $225 $ $4,294 -$3, , , $231 $ $0 $ , , $238 $ $4,294 $3, , , $245 $ $8,588 $7, , , $251 $ $12,882 $10, , , $258 $ $17,176 $14, , , $264 $ $21,470 $17, , , $271 $ $25,764 $20, , , $278 $224 Last year of traffic analysis $30,059 $23,963 Last year of benefitcost analysis 2039 Base (hrs) VHT Build (hrs) Last year of traffic analysis , , $284 $ $34,353 $27, , , $291 $ $38,647 $30,083 Total Project Life Benefit Benefit (hrs) Constant Benefit ($) Present Value of Savings ($) Year Last year of benefitcost analysis 2039 Base (miles) Build (miles) Benefit (miles) 996, , $297 $ $42,941 -$67,263 Total Project Life Benefit 8,546 $4,692 $4,055 VMT Constant Benefit ($) Present Value of Savings ($) BCA Workbook CSAH 57 Signal Page 4 of 5

52 Benefit Cost Analysis Workbook Crash Data Crash Analysis Crash Base Base Build Values Corridor AADT 11,300 11,300 16,775 16,775 ($ per crash) Reduction 44% 44% Fatal $ 11,100,000 Crash A $ 600,000 Severity B $ 180,000 (5 year C $ 87,000 data) PDO $ 7, $ 79, $ 44, $ 117, $ 65,841 Year Crash Calculations Base Build Annual Forecast Annual Forecast Number of Crashes Estimated Cost Number of Crashes Estimated Cost Constant Benefit ($) Present Value of Savings ($) First year of traffic analysis $82, $ 46,143 $ 36,255 $ 36, $85, $ 47,934 $ 37,662 $ 37,215 First year of benefitcost analysis $88, $ 49,724 $ 39,069 $ 38, $91, $ 51,515 $ 40,476 $ 39, $95, $ 53,306 $ 41,883 $ 39, $98, $ 55,097 $ 43,290 $ 40, $101, $ 56,887 $ 44,697 $ 41, $104, $ 58,678 $ 46,104 $ 42, $107, $ 60,469 $ 47,511 $ 43, $111, $ 62,260 $ 48,918 $ 43, $114, $ 64,050 $ 50,325 $ 44, $117, $ 65,841 $ 51,732 $ 45, $120, $ 67,632 $ 53,139 $ 46, $123, $ 69,423 $ 54,546 $ 46, $127, $ 71,213 $ 55,953 $ 47, $130, $ 73,004 $ 57,360 $ 47, $133, $ 74,795 $ 58,767 $ 48, $136, $ 76,586 $ 60,174 $ 49, $139, $ 78,376 $ 61,582 $ 49,682 Last year of traffic analysis $143, $ 80,167 $ 62,989 $ 50, $146, $ 81,958 $ 64,396 $ 50,728 Last year of benefitcost analysis $149, $ 83,749 $ 65,803 $ 51,221 Total Project Life Benefit $ 1,048,717 $ 906,706 BCA Workbook CSAH 57 Signal Page 5 of 5

53 INTERSECTION CONTROL EVALUATION Trunk Highway 22 and Blue Earth CSAH 26 (227th Street) Mankato, Minnesota November 2018

54 Trunk Highway 22 and Blue Earth CSAH 26 (227th Street) Intersection Control Evaluation Mankato, Blue Earth County, Minnesota I hereby certify that this report was prepared by me or under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. Mike Bittner, PE, PTOE Date: 11/28/2018 License No: Approved: MnDOT District 7 Traffic Engineer Date MnDOT District 7 State Aid Engineer Date ICE Report TH 22 and CSAH 3 (North Victory Drive) i

55 Contents Background and Study Area... 1 Roadway Characteristics... 1 Study Intersection Configuration... 1 Access Spacing... 1 Traffic Volumes... 1 Warrant Analysis... 3 Traffic Operations... 3 Existing Conditions Traffic Operations... 3 Future Conditions Traffic Operations... 4 Queue Analysis... 5 Multimodal Roundabout Considerations... 5 Truck Considerations... 5 Crash History... 5 Corridor Vision... 6 Summary and Recommendation... 7 Appendix A. PM Peak Hour Traffic Simulation Results ICE Report TH 22 and CSAH 3 (North Victory Drive) ii

56 Background and Study Area As part of the Trunk Highway (TH) 22 Corridor Study, intersection control revisions are being considered at the intersection of TH 22 and Blue Earth County State Aid Highway 26/227th Street (to be referred to as CSAH 26) just north of Mankato. The objective of this Intersection Control Evaluation report is to determine the optimal intersection control to improve future traffic capacity and reduce crash potential. The following intersection control options were evaluated:» Traffic signal (existing control)» Hybrid 2x1 Roundabout with minor right turn lanes The study area can be seen in Figure 1. Roadway Characteristics TH 22 is functionally classified as a principal arterial and CSAH 26 is classified as a major collector. At the intersection, TH 22 has a 55 mph posted speed limit and CSAH 26 has a 40 mph posted speed limit. STUDY INTERSECTION CONFIGURATION The intersection is signal controlled. The lane configuration is:» Southbound: Two through lanes, dedicated right and left turn lanes» Northbound: Two through lanes, dedicated right and left turn lanes» Eastbound: One through lane, dedicated right and left turn lanes» Westbound: One through lane, dedicated right and left turn lanes ACCESS SPACING North of CSAH 26, the closest public access point is 583 rd Avenue which is 4,800 feet (0.90 miles) away. South of CSAH 26, the closest public access point is Augusta Drive which is 2,640 feet (0.5 miles) away. These adjacent public access points are stop controlled on the minor approaches, however a future roundabout is planned at Augusta Drive. MnDOT access spacing guidelines for urban/urbanizing principal arterials (Mn/DOT Access Management Manual [2008]) recommends 1/2 mile access spacing primary full movement intersections, and 1/4 mile access spacing for secondary. Hensonshire Drive is approximately 250 feet to the west of the intersection (660 feet full access spacing recommendation) and should be considered for reduced access as traffic volumes increase along CSAH 26. Access spacing and associated access recommendations are being developed with the larger TH 22 Corridor Study. Traffic Volumes Existing and projected average daily traffic volumes (ADT) and peak hour turning movements at the study intersection can be seen in Figure 1. Existing volumes are 2017 traffic volumes that were collected for the TH 22 Corridor Study. Traffic projections for 2030 and 2045 were developed in the corridor study through a review of historic traffic patterns and growth rates as well as expected land use changes in the area. Traffic volumes on TH 22 are four to five times more than CSAH 26 volumes causing an unbalanced intersection, which is important when considering alternatives. Based on discussions with the TH 22 corridor study Technical Advisory Committee, it has been established that 2045 traffic projections documented in this report reflect an aggressive growth scenario average annual growth rates and 2030 ADT estimates were calculated from 2017 daily intersection counts and assumed 2.6 percent to the north and south, 2.9 percent to the east, and 1.4 percent to the west. As such, if less intense development occurs in the area than assumed for the 2045 traffic projections, 2030 traffic projections presented in this document could approximate 2045 projections in a more moderate growth scenario. ICE Report TH 22 and Blue Earth CSAH 26 (227th Street) 1

57 Figure 1 Study Area Details ICE Report TH 22 and Blue Earth CSAH 26 (227th Street) 2

58 Warrant Analysis Traffic signal warrants from the Minnesota Manual on Uniform Traffic Control Devices were evaluated under existing and projected traffic volumes. Minor approach right turns were omitted from this analysis given the presence of eastbound and westbound right turn lanes on CSAH 26. It is typical for a traffic signal or roundabout to be considered for MnDOT roadways when Warrant 1 is met (Scott Thompson MnDOT D7). Under existing volumes, Warrant 2: Four Hour Vehicular Volume and Warrant 3: Peak Hour are met. By 2030, Warrant 1b: Interruption of Continuous Traffic is also expected to be met. Criteria Table 1 Signal Warrant Analysis (2017) Hours Met Hours Required Warrants Met Warrant 1a: Minimum Vehicular Volume 1 8 Not Met Warrant 1b: Interruption of Continuous Traffic 6 8 Not Met Warrant 2: Four Hour Vehicular Volume 4 4 Met Warrant 3: Peak Hour 1 1 Met Warrant 7: Crash Experience 1* 8 Not Met Multi way Stop Applications (MWSA) 2 8 Not Met *Hours meeting traffic volume component for Warrant 7 Table 2 Signal Warrant Analysis (2030) Hours Hours Criteria Warrants Met Met Required Warrant 1a: Minimum Vehicular Volume 1 8 Not Met Warrant 1b: Interruption of Continuous Traffic 11 8 Met Warrant 2: Four Hour Vehicular Volume 8 4 Met Warrant 3: Peak Hour 4 1 Met Warrant 7: Crash Experience 6* 8 Not Met Multi way Stop Applications (MWSA) 4 8 Not Met *Hours meeting traffic volume component for Warrant 7 Traffic Operations Existing Conditions Traffic Operations Intersection operations for both signal control and roundabout control were evaluated using the Vissim software. Control delay for each level of service threshold can be seen in Table 3. Per MnDOT Access Management Manual and FHWA guidance, LOS E or worse will be considered an operational deficiency where mitigation should be discussed. Table 3 Highway Capacity Manual Intersection Level of Service Thresholds Control Delay Unsignalized Signalized Level of Service (LOS) A > > B > > C > > D > > E > 50 > 80 F ICE Report TH 22 and Blue Earth CSAH 26 (227th Street) 3

59 Under existing traffic volumes, intersection geometry, and signal control, the intersection operates at LOS C in the AM peak hour and LOS B in the PM peak hour, with no approach operating worse than LOS D. The existing signalized intersection would benefit from connection/interoperability of traffic signals throughout the corridor. Future Conditions Traffic Operations Vissim models were developed for a 24 hour time period under projected 2030 and 2045 traffic volumes. Roundabout simulation assumes a 2x1 hybrid roundabout at CSAH 26 with minor right turn lanes and no right turn bypass lanes. This alternative helped to balance out the 5:1 major to minor approach volume discrepancy, but minor approach delay times will likely be longer than major approach delay times. Minor approaches are expected to operate at LOS D or better for future conditions. Configurations for both future alternatives can be seen in Table 7. Simulation results indicate that a roundabout will operate with less control delay than a traffic signal during all hours of the day under both 2030 and 2045 traffic conditions. Both traffic control options are expected to operate at LOS C or better through In 2030, a roundabout is expected to operate with less than 10 seconds of control delay throughout the day, while a signal is expected to operate with around 20 seconds of control delay between 8 am and 5 pm. Similar delays are expected under 2045 traffic volumes. As part of a larger network wide modelling effort the impact that placing meters on roundabout approaches to assign right of way was studied for 2045 conditions, but it was found to have negligible impacts at the study intersection. As such, subsequent analysis presented in this ICE report assumes no roundabout metering is present. Figure and 2045 Modelled Intersection Delays at CSAH Note: LOS thresholds on this graphic are for unsignalized intersections. See Table 1 for signalized LOS thresholds. Table 4 Average Intersection Delays at CSAH 26 (24 hour Average) Traffic Control 2030 Average Delay (24 Hour 2045 Average Delay (24 Hour Average) Average) Traffic Signal 13.8 seconds 15.4 seconds Roundabout 2.8 seconds 4.2 seconds P.M. peak hour traffic operations by approach for each traffic control option can be seen in Appendix A. ICE Report TH 22 and Blue Earth CSAH 26 (227th Street) 4

60 Queue Analysis Average PM peak hour simulated queue lengths were evaluated, with neither a signal nor a roundabout expected to have major queuing issues through Table 5 Average 2030 and 2045 Queue Lengths Approach Signal* Roundabout Signal* Roundabout Northbound Southbound Eastbound Westbound Queue lengths shown in feet *Reflects longest average queue on each approach under signal control Multimodal Roundabout Considerations Reduced vehicle speeds associated with roundabout control allow more time for drivers and pedestrians to interact with each other, and the presence of raised splitter islands also simplifies the task of pedestrian crossings by allow pedestrians to consider one direction of conflicting traffic at a time. On street bicycle facilities are not in place nor are they planned, so most cyclists will use a roundabout like pedestrians. Note that pedestrian crossings are being evaluated on a corridor level as part of the TH 22 corridor study, with recommendations being made related to potential dedicated pedestrian crossings at appropriate locations. Truck Considerations Roundabouts have been successfully constructed on many Minnesota trunk highways, including two on the TH 22 corridor at Adams Street and Madison Avenue. With proper roundabout design characteristics such as a sufficient inscribed circle diameter and truck aprons with curbs designed to prevent load shifting, trucks can navigate roundabouts without issue. Information from MnDOT s Right of Way Mapping and Monitoring web application indicates approximately 280 feet of right of way at CSAH 26, with MnDOT recommending roundabout diameters of 150 to 200 feet for urban two lane roundabouts (MnDOT Road Design Manual Table A [2009]). Crash History Crash data was obtained from MnDOT for the time period between January 2011 and December In the fiveyear period, two crashes were reported. Both crashes were right angle crashes that did not result in injuries. To evaluate the expected safety impact from conversion from signal control to roundabout control, the FHWA Surrogate Safety Assessment Model (SSAM) was used. The SSAM uses vehicle trajectory information from Vissim simulation models to identify the number of rear end, lane change, and crossing conflicts. Simulation results from a full 24 hour Vissim model were used for this analysis. Under 2030 traffic volumes, the total number of conflicts is expected to be reduced by 29 percent and rear end conflicts are expected to be reduced by 20 percent. By 2045, the change in conflicts is less pronounced, however under roundabout control the total number of conflicts is still expected to be reduced by seven percent. Lane change and crossing conflicts are also expected to be reduced under both 2030 and 2045 conditions. In addition to the overall conflict reduction, MnDOT data in the Traffic Safety Fundamentals Handbook (2015) indicates a 60 to 70 percent reduction in severe crashes (injury or fatal crashes) with a hybrid roundabout compared to a signal. ICE Report TH 22 and Blue Earth CSAH 26 (227th Street) 5

61 Table 6 Conflict Comparison Between Traffic Signal and Roundabout Conflicts Alternative Rear Lane End Change Crossing Total Rear Lane End Change Crossing Total Signal Roundabout % Chg. W/ Roundabout 20% 69% 95% 29% 1% 38% 83% 7% Corridor Vision Throughout the TH 22 corridor study, it has been established that the future vision for the TH 22 corridor through urbanized Mankato is a roundabout corridor. As part of a larger traffic simulation effort as part of the corridor study it was found that corridor wide operations (CSAH 26 to Hoffman Road) are improved with a roundabout corridor compared to a signal corridor (see Figure 3 and Figure 4). Under 2030 traffic conditions, network wide delay is lower with a roundabout corridor for every hour of the day, and under 2045 conditions roundabout operations are better than signal operations for most of the day except between 3 pm and 7 pm. Metered roundabouts can however be used in the future at congested locations, and simulation results indicate operations much closer to a signal corridor in 2045 if metering is used, however delays still are expected to exceed signal operations between 4 pm and 6 pm. More specific details related to the corridor wide modelling effort and results can be seen in the Vissim Urban Analysis Report which is part of the TH 22 Corridor Study. Figure Network Delay Comparison ICE Report TH 22 and Blue Earth CSAH 26 (227th Street) 6

62 Figure Network Delay Comparison Summary and Recommendation A multilane roundabout is expected to operate with fewer delays and conflicts than a traffic signal through 2045 (see Figure 2) and is also expected to reduce the potential for severe crashes. A future roundabout will align with the future corridor vision of a roundabout corridor, is consistent with recently constructed roundabouts at both Adams Street and Madison Avenue, and can fit within available right of way. As such, a multilane roundabout is recommended at the intersection of TH 22 and CSAH 26. Given the acceptable future operations under signal control and a low crash frequency, a 2x1 roundabout with eastbound and westbound right turn lanes can be a long term improvement, focusing corridor improvements on locations with more imminent operations and safety issues that need to be resolved. Table 7 Analysis Summary ICE Report TH 22 and Blue Earth CSAH 26 (227th Street) 7

63 Appendix A PM Peak Hour Traffic Simulation Results

64 TH 22 VISSIM Analysis MnDOT District 7 _2030_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Blue Earth CSAH 26 Left D Northbound Thru A 13.7 B Right A Left A Southbound Thru C 19.9 B Right A B Left B Eastbound Thru D 15.4 B Right A Left C Westbound Thru C 27.9 C Right A TH 22 and Augusta Drive Left D Northbound Thru B 18.4 B Right A Left D Southbound Thru B 17.2 B Right A B Left C Eastbound Thru C 20.7 C Right A Left C Westbound Thru D 26.1 C Right A TH 22 and North Victory Drive Left D Northbound Thru C 31.7 C Right A Left E Southbound Thru C 25.4 C Right B C Left D Eastbound Thru D 29.3 C Right B Left D Westbound Thru D 41.2 D Right A TH 22 and TH 14 North Ramps Northbound Southbound Westbound Left C B Thru A Thru C C 18.9 B Right A Left D D Right B TH 22 and TH 14 South Ramps Northbound Southbound Eastbound Thru B A Right A Left F B 13.2 B Thru B Left D B Right A TH 22 and Adams Street Left E Northbound Thru C 27.2 C Right A Left C Southbound Thru B 16.1 B Right B C Left D Eastbound Thru D 35.6 D Right B Left D Westbound Thru E 24.4 C Right A

65 TH 22 VISSIM Analysis MnDOT District 7 _2030_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Madison Avenue Left D Northbound Thru B 19.7 B Right A Left D Southbound Thru D 44.4 D Right C C Left C Eastbound Thru D 31.7 C Right A Left C Westbound Thru D 35.7 D Right A TH 22 and Bassett Drive Left E Northbound Thru C 28.1 C Right A Left E Southbound Thru C 38.5 D Right B C Left C Eastbound Thru D 31.3 C Right B Left D Westbound Thru D 36.1 D Right A TH 22 and Hoffman Road Left E Northbound Thru C 23.7 C Right A Left D Southbound Thru C 28.4 C Right A C Left D Eastbound Thru D 43.1 D Right A Left C Westbound Thru D 27.4 C Right A Adams Street and Haefner Drive Left A Northbound Thru A 5.3 A Right A Left A Southbound Thru A 4.6 A Right A A Left A Eastbound Thru A 4.6 A Right A Left A Westbound Thru A 8.3 A Right A Madison Avenue and Haefner Drive Left A Northbound Thru A 6.8 A Right A Left A Southbound Thru A 3.2 A Right A A Left A Eastbound Thru A 5.0 A Right A Left A Westbound Thru A 4.0 A Right A

66 TH 22 VISSIM Analysis MnDOT District 7 _2030_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 VISSIM Network Results _2030_Build Traffic Signals_24 Hours Avg Delay (s) Avg Speed TRAVTMTOT DELAYTOT DEMAND Vehicles Distance (mi) (MPH) (ALL) (ALL) LATENT Avg St Dev VISSIM Travel Time Results _2030_Build Traffic Signals_24 Hours Travel Times NB TH 22 to NB TH 22 NB TH 22 to US Hwy 14 SB TH 22 to SB TH 22 SB TH 22 to US Hwy 14 Run # 1 Run # 2 Run # 3 Run # 4 Run # 5 AVG

67 TH 22 VISSIM Analysis MnDOT District 7 _2030_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Blue Earth CSAH 26 Left A Northbound Thru A 3.1 A Right A Left A Southbound Thru A 5.4 A Right A A Left A Eastbound Thru A 6.8 A Right A Left B Westbound Thru B 12.8 B Right A TH 22 and Augusta Drive Left A Northbound Thru A 4.7 A Right A Left A Southbound Thru A 4.1 A Right A B Left F Eastbound Thru C 38.2 E Right C Left E Westbound Thru A 24.5 C Right A TH 22 and North Victory Drive Left A Northbound Thru A 5.8 A Right A Left D Southbound Thru C 20.9 C Right A C Left C Eastbound Thru B 9.4 A Right A Left E Westbound Thru C 26.8 D Right A TH 22 and TH 14 North Ramps Northbound Southbound Westbound Left C B Thru A Thru C C 23.2 C Right A Left D D Right B TH 22 and TH 14 South Ramps Northbound Southbound Eastbound Thru A A Right A Left F C 14.4 B Thru B Left D B Right A TH 22 and Adams Street Left C Northbound Thru C 18.6 C Right A Left C Southbound Thru C 17.7 C Right A C Left D Eastbound Thru E 30.9 D Right B Left C Westbound Thru B 7.3 A Right A

68 TH 22 VISSIM Analysis MnDOT District 7 _2030_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Madison Avenue Left B Northbound Thru B 11.2 B Right A Left B Southbound Thru A 7.7 A Right A B Left C Eastbound Thru B 12.5 B Right A Left C Westbound Thru B 13.4 B Right A TH 22 and Bassett Drive Left A Northbound Thru A 5.8 A Right A Left B Southbound Thru B 10.4 B Right A A Left B Eastbound Thru B 6.7 A Right A Left A Westbound Thru A 5.6 A Right A TH 22 and Hoffman Road Left A Northbound Thru A 3.2 A Right A Left A Southbound Thru A 4.1 A Right A A Left D Eastbound Thru B 21.6 C Right A Left B Westbound Thru A 6.8 A Right A Adams Street and Haefner Drive Left A Northbound Thru A 4.1 A Right A Left A Southbound Thru A 3.4 A Right A A Left A Eastbound Thru A 2.4 A Right A Left A Westbound Thru A 5.4 A Right A Madison Avenue and Haefner Drive Left A Northbound Thru A 4.9 A Right A Left A Southbound Thru A 3.1 A Right A A Left A Eastbound Thru A 2.3 A Right A Left A Westbound Thru A 3.3 A Right A

69 TH 22 VISSIM Analysis MnDOT District 7 _2030_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 VISSIM Network Results _2030_Roundabouts_24 hours 2x2 Avg Delay (s) Avg Speed TRAVTMTOT DELAYTOT DEMAND Vehicles Distance (mi) (MPH) (ALL) (ALL) LATENT Avg St Dev VISSIM Travel Time Results _2030_Roundabouts_24 hours 2x2 Travel Times NB TH 22 to NB TH 22 NB TH 22 to US Hwy 14 SB TH 22 to SB TH 22 SB TH 22 to US Hwy 14 Run # 1 Run # 2 Run # 3 Run # 4 Run # 5 AVG #REF! #REF! 178.8

70 TH 22 VISSIM Analysis MnDOT District 7 _2045_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Blue Earth CSAH 26 Left D Northbound Thru B 19.7 B Right A Left A Southbound Thru C 24.0 C Right A C Left D Eastbound Thru D 17.2 B Right A Left D Westbound Thru D 35.3 D Right A TH 22 and Augusta Drive Left D Northbound Thru B 22.0 C Right A Left D Southbound Thru D 34.9 C Right B C Left D Eastbound Thru C 22.3 C Right A Left C Westbound Thru D 29.3 C Right A TH 22 and North Victory Drive Left D Northbound Thru C 33.0 C Right A Left E Southbound Thru C 31.0 C Right B C Left E Eastbound Thru D 38.9 D Right B Left D Westbound Thru D 43.0 D Right A TH 22 and TH 14 North Ramps Northbound Southbound Westbound Left C A Thru A Thru D D 28.3 C Right A Left D D Right B TH 22 and TH 14 South Ramps Northbound Southbound Eastbound Thru A A Right A Left F B 13.3 B Thru B Left D B Right A TH 22 and Adams Street Left F Northbound Thru C 46.0 D Right B Left C Southbound Thru B 18.0 B Right A C Left D Eastbound Thru D 38.4 D Right B Left D Westbound Thru E 28.9 C Right A

71 TH 22 VISSIM Analysis MnDOT District 7 _2045_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Madison Avenue Left D Northbound Thru B 17.9 B Right A Left E Southbound Thru E 52.1 D Right C D Left D Eastbound Thru D 32.6 C Right B Left C Westbound Thru D 36.5 D Right A TH 22 and Bassett Drive Left E Northbound Thru C 32.4 C Right A Left E Southbound Thru D 47.4 D Right B D Left C Eastbound Thru D 28.6 C Right B Left E Westbound Thru D 41.0 D Right B TH 22 and Hoffman Road Left E Northbound Thru C 27.2 C Right A Left E Southbound Thru D 36.3 D Right A C Left D Eastbound Thru D 45.3 D Right A Left D Westbound Thru D 33.3 C Right B Adams Street and Haefner Drive Left A Northbound Thru A 6.1 A Right A Left A Southbound Thru A 4.5 A Right A A Left A Eastbound Thru A 6.0 A Right A Left A Westbound Thru A 8.8 A Right B Madison Avenue and Haefner Drive Left B Northbound Thru A 9.6 A Right A Left A Southbound Thru A 3.6 A Right A A Left A Eastbound Thru A 5.1 A Right A Left A Westbound Thru A 5.0 A Right A

72 TH 22 VISSIM Analysis MnDOT District 7 _2045_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 VISSIM Network Results _2045_Build Traffic Signals_24 Hours Avg Delay (s) Avg Speed TRAVTMTOT DELAYTOT DEMAND Vehicles Distance (mi) (MPH) (ALL) (ALL) LATENT Avg St Dev VISSIM Travel Time Results _2045_Build Traffic Signals_24 Hours Travel Times NB TH 22 to NB TH 22 NB TH 22 to US Hwy 14 SB TH 22 to SB TH 22 SB TH 22 to US Hwy 14 Run # 1 Run # 2 Run # 3 Run # 4 Run # 5 AVG

73 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Blue Earth CSAH 26 Left A Northbound Thru A 3.6 A Right A Left A Southbound Thru B 10.6 B Right A A Left A Eastbound Thru A 8.0 A Right A Left C Westbound Thru D 25.9 D Right A TH 22 and Augusta Drive Left A Northbound Thru A 6.2 A Right A Left A Southbound Thru A 6.9 A Right A F Left F Eastbound Thru F F Right F Left F Westbound Thru F F Right F TH 22 and North Victory Drive Left B Northbound Thru A 8.2 A Right A Left E Southbound Thru E 37.8 E Right C D Left E Eastbound Thru C 24.0 C Right B Left F Westbound Thru E 55.2 F Right A TH 22 and TH 14 North Ramps Northbound Southbound Westbound Left C B Thru A Thru D C 24.0 C Right A Left D D Right B TH 22 and TH 14 South Ramps Northbound Southbound Eastbound Thru B A Right A Left E C 14.5 B Thru B Left E B Right A TH 22 and Adams Street Left D Northbound Thru D 31.3 D Right B Left D Southbound Thru D 21.6 C Right A F Left F Eastbound Thru F F Right F Left F Westbound Thru F F Right F

74 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Madison Avenue Left F Northbound Thru E 44.4 E Right B Left B Southbound Thru A 8.5 A Right A F Left F Eastbound Thru F F Right F Left F Westbound Thru F F Right E TH 22 and Bassett Drive Left B Northbound Thru B 10.4 B Right A Left D Southbound Thru C 24.5 C Right B C Left C Eastbound Thru C 10.1 B Right A Left D Westbound Thru C 17.2 C Right A TH 22 and Hoffman Road Left A Northbound Thru A 4.1 A Right A Left B Southbound Thru A 8.7 A Right A D Left F Eastbound Thru F F Right B Left F Westbound Thru D 27.6 D Right A Adams Street and Haefner Drive Left F Northbound Thru F F Right E Left F Southbound Thru F 91.8 F Right F F Left D Eastbound Thru A 14.7 B Right A Left F Westbound Thru F F Right F Madison Avenue and Haefner Drive Left E Northbound Thru B 25.6 D Right A Left E Southbound Thru E 34.9 D Right D C Left A Eastbound Thru A 3.2 A Right A Left C Westbound Thru D 22.8 C Right A

75 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 VISSIM Network Results _2045_Roundabouts_24 hours 2x2 Avg Delay (s) Avg Speed TRAVTMTOT DELAYTOT DEMAND Vehicles Distance (mi) (MPH) (ALL) (ALL) LATENT Avg St Dev VISSIM Travel Time Results _2045_Roundabouts_24 hours 2x2 Travel Times NB TH 22 to NB TH 22 NB TH 22 to US Hwy 14 SB TH 22 to SB TH 22 SB TH 22 to US Hwy 14 Run # 1 Run # 2 Run # 3 Run # 4 Run # 5 AVG #REF! #REF!

76 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts Metered_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Blue Earth CSAH 26 Left A Northbound Thru A 4.5 A Right A Left A Southbound Thru B 11.3 B Right B A Left A Eastbound Thru A 8.2 A Right A Left D Westbound Thru E 33.9 D Right A TH 22 and Augusta Drive Left B Northbound Thru A 9.2 A Right A Left A Southbound Thru B 11.1 B Right A D Left F Eastbound Thru E 70.5 F Right E Left F Westbound Thru C 73.1 F Right D TH 22 and North Victory Drive Left C Northbound Thru B 12.6 B Right A Left E Southbound Thru E 41.2 E Right C C Left C Eastbound Thru A 11.0 B Right A Left D Westbound Thru C 21.0 C Right A TH 22 and TH 14 North Ramps Northbound Southbound Westbound Left D B Thru A Thru D D 26.5 C Right A Left D D Right B TH 22 and TH 14 South Ramps Northbound Southbound Eastbound Thru B A Right A Left F C 14.2 B Thru B Left E B Right A TH 22 and Adams Street Left E Northbound Thru E 37.2 E Right B Left D Southbound Thru D 23.2 C Right A E Left F Eastbound Thru F 55.3 F Right E Left F Westbound Thru F 82.1 F Right D

77 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts Metered_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Madison Avenue Left F Northbound Thru F 54.0 F Right B Left D Southbound Thru C 19.8 C Right A E Left E Eastbound Thru C 29.3 D Right B Left F Westbound Thru F 50.7 F Right B TH 22 and Bassett Drive Left B Northbound Thru B 11.7 B Right A Left D Southbound Thru D 25.8 D Right B C Left C Eastbound Thru C 10.1 B Right A Left C Westbound Thru B 12.5 B Right A TH 22 and Hoffman Road Left A Northbound Thru A 8.7 A Right A Left C Southbound Thru C 16.4 C Right A C Left F Eastbound Thru E 46.2 E Right A Left D Westbound Thru C 14.3 B Right A Adams Street and Haefner Drive Left E Northbound Thru C 23.2 C Right A Left F Southbound Thru F F Right F E Left B Eastbound Thru A 6.5 A Right A Left F Westbound Thru F 86.6 F Right F Madison Avenue and Haefner Drive Left B Northbound Thru A 9.0 A Right A Left A Southbound Thru A 5.6 A Right A A Left A Eastbound Thru A 2.8 A Right A Left A Westbound Thru A 6.3 A Right A

78 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts Metered_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 VISSIM Network Results _2045_Roundabouts Metered_24 hours 2x2 Avg Delay (s) Avg Speed TRAVTMTOT DELAYTOT DEMAND Vehicles Distance (mi) (MPH) (ALL) (ALL) LATENT Avg St Dev VISSIM Travel Time Results _2045_Roundabouts Metered_24 hours 2x2 Travel Times NB TH 22 to NB TH 22 NB TH 22 to US Hwy 14 SB TH 22 to SB TH 22 SB TH 22 to US Hwy 14 Run # 1 Run # 2 Run # 3 Run # 4 Run # 5 AVG #REF! #REF!

79 INTERSECTION CONTROL EVALUATION Trunk Highway 22 and Blue Earth CSAH 3 (North Victory Drive) Mankato, Minnesota November 2018

80 Trunk Highway 22 and Blue Earth CSAH 3 (North Victory Drive) Intersection Control Evaluation Mankato, Blue Earth County, Minnesota I hereby certify that this report was prepared by me or under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. Mike Bittner, PE, PTOE Date: 11/28/2018 License No: Approved: MnDOT District 7 Traffic Engineer Date MnDOT District 7 State Aid Engineer Date ICE Report TH 22 and Blue Earth CSAH 3 (N Victory Drive) i

81 Contents Background and Study Area... 1 Roadway Characteristics... 1 Study Intersection Configuration... 1 Access Spacing... 1 Traffic Volumes... 1 Warrant Analysis... 3 Traffic Operations... 3 Existing Conditions Traffic Operations... 3 Future Conditions Traffic Operations... 3 Queue Analysis... 4 Multimodal Roundabout Considerations... 5 Truck Considerations... 5 Crash History... 5 Corridor Vision... 6 Summary and Recommendation... 8 Appendices A. PM Peak Hour Traffic Simulation Results ICE Report TH 22 and Blue Earth CSAH 3 (N Victory Drive) ii

82 Background and Study Area As part of the Trunk Highway (TH) 22 Corridor Study, intersection control revisions are being considered at the intersection of TH 22 and CSAH 3/North Victory Drive (to be referred to as CSAH 3) in Mankato. The objective of this Intersection Control Evaluation report is to determine the optimal intersection control to improve future traffic capacity and reduce crash potential. The following intersection control options were evaluated:» Traffic signal (existing control)» Multilane Roundabout with bypasses The study area can be seen in Figure 1. Roadway Characteristics TH 22 is functionally classified as a principal arterial and CSAH 3 is classified as a minor arterial west of TH 22 and a major collector east of TH 22. At the intersection, TH 22 has a 45 mph posted speed limit and CSAH 3 has a posted speed limit of 40 mph. STUDY INTERSECTION CONFIGURATION The intersection is signal controlled. The lane configuration is:» Southbound: Two through lanes, dedicated right and left turn lanes» Northbound: Two through lanes, dedicated right turn lane and double left turn lane» Eastbound: Two through lanes, dedicated right and left turn lanes» Westbound: Two through lanes, dedicated right and left turn lanes ACCESS SPACING North of Victory Drive, the closest public access point is two way stop controlled Augusta Drive which is 2,640 feet (0.5 miles) away. South of Victory Drive, the closest public access point is stop controlled Premier Drive, which is a right in/right out access that is 1,330 feet (0.25 miles) away. The signalized US 14 north ramps are 2000 feet (0.38 miles) south of Victory drive. MnDOT access spacing guidelines for urban/urbanizing principal arterials (Mn/DOT Access Management Manual [2008]) recommend 1/2 mile access spacing for primary full movement intersections, and 1/4 mile access spacing for secondary intersections. Access spacing and associated access recommendations are being developed with the larger TH 22 Corridor Study. Traffic Volumes Existing and projected average daily traffic volumes (ADT) and peak hour turning movements at the study intersection can be seen in Figure 1. Existing volumes are 2017 traffic volumes that were collected for the TH 22 Corridor Study. Traffic projections for 2030 and 2045 were developed in the corridor study through a review of historic traffic patterns and growth rates as well as expected land use changes in the area. Based on discussions with the TH 22 corridor study Technical Advisory Committee, it has been established that 2045 traffic projections documented in this report reflect an aggressive growth scenario average annual growth rates and 2030 ADT estimates were calculated from 2017 daily intersection counts and assumed 2.6 percent to the north and to the south, 2.5 percent to the east, and 2.1 percent to the west. As such, if less intense development occurs in the area than assumed for the 2045 traffic projections, 2030 traffic projections presented in this document could approximate 2045 projections in a more moderate growth scenario. ICE Report TH 22 and Blue Earth CSAH 3 (N Victory Drive) 1

83 Figure 1 Study Area Details ICE Report TH 22 and Blue Earth CSAH 3 (N Victory Drive) 2

84 Warrant Analysis Traffic signal warrants from the Minnesota Manual on Uniform Traffic Control Devices were evaluated under existing and projected traffic volumes. Minor approach right turns were omitted from this analysis given the presence of eastbound and westbound right turn lanes on CSAH 3. It is typical for a traffic signal or roundabout to be considered for MnDOT roadways when Warrant 1 is met (Scott Thompson MnDOT D7). Under existing volumes Warrants 1, 2, and 3 are all met. Table 1 Signal Warrant Analysis (2017) Criteria Hours Hours Met Required Warrants Met Warrant 1a: Minimum Vehicular Volume 14 8 Met Warrant 1b: Interruption of Continuous Traffic 13 8 Met Warrant 2: Four Hour Vehicular Volume 13 4 Met Warrant 3: Peak Hour 12 1 Met Traffic Operations Existing Conditions Traffic Operations Intersection operations for both signal control and roundabout control were evaluated using the Vissim software. Control delay for each level of service threshold can be seen in Table 2. Per MnDOT Access Management Manual and FHWA guidance, LOS E or worse will be considered an operational deficiency where mitigation should be discussed. Table 2 Highway Capacity Manual Intersection Level of Service Thresholds Control Delay Unsignalized Signalized Level of Service (LOS) A > > B > > C > > D > > E > 50 > 80 F Under existing traffic volumes, intersection geometry, and signal control, the intersection operates at LOS C during both the AM and PM peak hours, with no approach operating worse than LOS D. The existing signalized intersection would benefit from connection/interoperability of traffic signals throughout the corridor. Future Conditions Traffic Operations Vissim models were developed for a 24 hour time period under projected 2030 and 2045 traffic volumes. Roundabout simulation assumes a multilane roundabout at CSAH 3, with right turn bypass lanes on all intersection approaches. Bypass lanes were assumed in both 2030 and 2045 simulations since modelled operations without them resulted in major delays and queue spillback issues. Configurations for both future alternatives can be seen in Table 6. Simulation results indicate that a roundabout will operate with less control delay than a traffic signal during all hours of the day under 2030 conditions, and for most hours (beside the PM peak) under 2045 conditions. In 2030, a traffic signal is expected to reach LOS D in the PM peak hour, while a roundabout is expected to operate with less than 20 seconds per vehicle throughout the day (LOS C or better). By 2045 the roundabout operates at LOS E during the PM peak period, however implementing roundabout metering to assign right of way to traffic is ICE Report TH 22 and Blue Earth CSAH 3 (N Victory Drive) 3

85 expected to improve 2045 PM roundabout operations to LOS D which is less delay than the signalized alternative. Outside of the 2045 PM peak hour, roundabout metering has a negligible impact on intersection delay. Figure and 2045 Modelled Intersection Delays Note: LOS thresholds on this graphic are for unsignalized intersections. See Table 2 for signalized LOS thresholds. Table 3 Average Control Delays (24 hour Average) Traffic Control 2030 Average Delay (24 Hour 2045 Average Delay (24 Hour Average) Average) Traffic Signal 22.2 seconds 22.9 seconds Roundabout 4.5 seconds 8.4 seconds Metered Roundabout 5.9 seconds P.M. peak hour traffic operations by approach for each traffic control option can be seen in Appendix A. Queue Analysis Average PM peak hour simulated queue lengths were evaluated. This analysis assumes no roundabout metering is in place. Under 2030 traffic volumes a signal and roundabout are expected to have average queues at or under 100 feet in length. By 2045 average roundabout queues are expected to exceed average signal queues on the southbound and westbound approaches, with average roundabout queue lengths of 228 and 172 feet, respectively. While some longer peak hour queues are expected under roundabout control by 2045, average queues throughout the day are expected to be less under roundabout control given the significantly reduced amount of delay during off peak hours. ICE Report TH 22 and Blue Earth CSAH 3 (N Victory Drive) 4

86 Table 4 Average 2030 and 2045 Queue Lengths Approach Signal* Roundabout Signal* Roundabout Northbound Southbound Eastbound Westbound Queue lengths shown in feet *Reflects longest average queue on each approach under signal control Multimodal Roundabout Considerations Reduced vehicle speeds associated with roundabout control allow more time for drivers and pedestrians to interact with each other, and the presence of raised splitter islands also simplifies the task of pedestrian crossings by allow pedestrians to consider one direction of conflicting traffic at a time. On street bicycle facilities are not in place nor are they planned, so most cyclists will use a roundabout like pedestrians. Note that pedestrian crossings are being evaluated on a corridor level as part of the TH 22 corridor study, with recommendations being made related to potential dedicated pedestrian crossings at appropriate locations. Truck Considerations Roundabouts have been successfully constructed on many Minnesota trunk highways, including two on the TH 22 corridor at Adams Street and Madison Avenue. With proper roundabout design characteristics such as a sufficient inscribed circle diameter and truck aprons with curbs designed to prevent load shifting, trucks can navigate roundabouts without issue. Information from MnDOT s Right of Way Mapping and Monitoring web application indicates 270 to 280 feet of right of way at CSAH 3, with MnDOT recommending roundabout diameters of 150 to 200 feet for urban two lane roundabouts (MnDOT Road Design Manual Table A [2009]). Crash History Crash data was obtained from MnDOT for the time period between January 2011 and December In the fiveyear period, 27 crashes were reported. Three crashes resulted in non incapacitating injuries and four crashes resulted in possible injuries. The crash distribution is as follows:» 11 rear end» 7 right angle» 3 sideswipe» 3 left turn» 1 head on» 1 run off the road» 1 other (not specified) Using the critical crash analysis methodology which applies statistical analysis to determine if the difference in observed and typical crash rates is statistically significant, the intersection crash rate is not above the critical crash rate, but is above the statewide average. To evaluate the expected safety impact from conversion from signal control to roundabout control (no roundabout metering), the FHWA Surrogate Safety Assessment Model (SSAM) was used. The SSAM uses vehicle trajectory ICE Report TH 22 and Blue Earth CSAH 3 (N Victory Drive) 5

87 information from Vissim simulation models to identify the number of rear end, lane change, and crossing conflicts. Simulation results from a full 24 hour Vissim model were used for this analysis. Under 2030 traffic volumes and roundabout control, the total number of conflicts is expected to be reduced by seven percent and rear end conflicts are expected to be reduced by 18 percent compared to a traffic signal. Due to increased congestion under roundabout control by 2045, an 18 percent increase in the total number of conflicts is expected in 2045, with rear end conflicts also expected to increase by four percent. While rear end conflicts are expected to increase, roundabout control results in more predictable rear end conflicts since there is no yellow signal phase that can cause drivers to abruptly stop. Lane change conflicts are expected to increase significantly under both 2030 and 2045 volumes, however these conflicts have a low potential to be severe. Reducing the crossing conflict rate is the biggest indicator of reducing severe crashes. MnDOT data in the Traffic Safety Fundamentals Handbook (2015) indicates a 60 to 70 percent reduction in severe crashes (injury or fatal crashes) with a multilane roundabout compared to a signal. Alternative Table 5 Conflict Comparison Between Traffic Signal and Roundabout Rear End Conflicts Lane Change Crossing Total Rear End Lane Change Crossing Signal Roundabout % Chg. W/ Roundabout 18% 97% 65% 7% 4% 150% 35% 18% Note: Roundabout conflicts were evaluated with no roundabout metering Corridor Vision Throughout the TH 22 corridor study, it has been established that the future vision for the TH 22 corridor through urbanized Mankato is a roundabout corridor. As part of a larger traffic simulation effort as part of the corridor study it was found that corridor wide operations (CSAH 26 to Hoffman Road) are improved with a roundabout corridor compared to a signal corridor (see Figure 3 and Figure 4). Under 2030 traffic conditions, network wide delay is lower with a roundabout corridor for every hour of the day, and under 2045 conditions roundabout operations are better than signal operations for most of the day except between 3 pm and 7 pm. Metered roundabouts can however be used in the future at congested locations, and simulation results indicate operations much closer to a signal corridor in 2045 if metering is used, however delays still are expected to exceed signal operations between 4 pm and 6 pm. More specific details related to the corridor wide modelling effort and results can be seen in the Vissim Urban Analysis Report which is part of the TH 22 Corridor Study. Total ICE Report TH 22 and Blue Earth CSAH 3 (N Victory Drive) 6

88 Figure Network Delay Comparison Figure Network Delay Comparison ICE Report TH 22 and Blue Earth CSAH 3 (N Victory Drive) 7

89 Summary and Recommendation A multilane roundabout is expected to operate with fewer delays than a traffic signal for all hours of the day through 2030, and for most the day through 2045 (except the PM peak hour see Figure 2). With roundabout metering in 2045, roundabout delays will be less than signal delays throughout the entire day. The roundabout will also significantly reduce injury and severe crash types. The application of roundabout metering under 2045 volumes is however expected to result in a roundabout operating with less delay than a traffic signal. Intersection conflicts are expected to be reduced with roundabout control through 2030, however roundabout conflicts are expected to exceed signal conflicts by While 2045 conflicts may be higher than signal conflicts, roundabouts reduce the potential for severe crashes and also result in more predictable rear end type conflicts given the removal of a yellow signal phase that can cause drivers to abruptly stop. The future construction of a roundabout will align with the future corridor vision of a roundabout corridor, is consistent with recently constructed roundabouts at both Adams Street and Madison Avenue, and can fit within available right of way. Based on the analysis presented in this report, a multilane roundabout with right turn bypass lanes is recommended at the intersection of TH 22 and CSAH 3. Table 6 Summary of Analysis ICE Report TH 22 and Blue Earth CSAH 3 (N Victory Drive) 8

90 Appendix A PM Peak Hour Traffic Simulation Results

91 TH 22 VISSIM Analysis MnDOT District 7 _2030_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Blue Earth CSAH 26 Left D Northbound Thru A 13.7 B Right A Left A Southbound Thru C 19.9 B Right A B Left B Eastbound Thru D 15.4 B Right A Left C Westbound Thru C 27.9 C Right A TH 22 and Augusta Drive Left D Northbound Thru B 18.4 B Right A Left D Southbound Thru B 17.2 B Right A B Left C Eastbound Thru C 20.7 C Right A Left C Westbound Thru D 26.1 C Right A TH 22 and North Victory Drive Left D Northbound Thru C 31.7 C Right A Left E Southbound Thru C 25.4 C Right B C Left D Eastbound Thru D 29.3 C Right B Left D Westbound Thru D 41.2 D Right A TH 22 and TH 14 North Ramps Northbound Southbound Westbound Left C B Thru A Thru C C 18.9 B Right A Left D D Right B TH 22 and TH 14 South Ramps Northbound Southbound Eastbound Thru B A Right A Left F B 13.2 B Thru B Left D B Right A TH 22 and Adams Street Left E Northbound Thru C 27.2 C Right A Left C Southbound Thru B 16.1 B Right B C Left D Eastbound Thru D 35.6 D Right B Left D Westbound Thru E 24.4 C Right A

92 TH 22 VISSIM Analysis MnDOT District 7 _2030_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Madison Avenue Left D Northbound Thru B 19.7 B Right A Left D Southbound Thru D 44.4 D Right C C Left C Eastbound Thru D 31.7 C Right A Left C Westbound Thru D 35.7 D Right A TH 22 and Bassett Drive Left E Northbound Thru C 28.1 C Right A Left E Southbound Thru C 38.5 D Right B C Left C Eastbound Thru D 31.3 C Right B Left D Westbound Thru D 36.1 D Right A TH 22 and Hoffman Road Left E Northbound Thru C 23.7 C Right A Left D Southbound Thru C 28.4 C Right A C Left D Eastbound Thru D 43.1 D Right A Left C Westbound Thru D 27.4 C Right A Adams Street and Haefner Drive Left A Northbound Thru A 5.3 A Right A Left A Southbound Thru A 4.6 A Right A A Left A Eastbound Thru A 4.6 A Right A Left A Westbound Thru A 8.3 A Right A Madison Avenue and Haefner Drive Left A Northbound Thru A 6.8 A Right A Left A Southbound Thru A 3.2 A Right A A Left A Eastbound Thru A 5.0 A Right A Left A Westbound Thru A 4.0 A Right A

93 TH 22 VISSIM Analysis MnDOT District 7 _2030_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 VISSIM Network Results _2030_Build Traffic Signals_24 Hours Avg Delay (s) Avg Speed TRAVTMTOT DELAYTOT DEMAND Vehicles Distance (mi) (MPH) (ALL) (ALL) LATENT Avg St Dev VISSIM Travel Time Results _2030_Build Traffic Signals_24 Hours Travel Times NB TH 22 to NB TH 22 NB TH 22 to US Hwy 14 SB TH 22 to SB TH 22 SB TH 22 to US Hwy 14 Run # 1 Run # 2 Run # 3 Run # 4 Run # 5 AVG

94 TH 22 VISSIM Analysis MnDOT District 7 _2030_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Blue Earth CSAH 26 Left A Northbound Thru A 3.1 A Right A Left A Southbound Thru A 5.4 A Right A A Left A Eastbound Thru A 6.8 A Right A Left B Westbound Thru B 12.8 B Right A TH 22 and Augusta Drive Left A Northbound Thru A 4.7 A Right A Left A Southbound Thru A 4.1 A Right A B Left F Eastbound Thru C 38.2 E Right C Left E Westbound Thru A 24.5 C Right A TH 22 and North Victory Drive Left A Northbound Thru A 5.8 A Right A Left D Southbound Thru C 20.9 C Right A C Left C Eastbound Thru B 9.4 A Right A Left E Westbound Thru C 26.8 D Right A TH 22 and TH 14 North Ramps Northbound Southbound Westbound Left C B Thru A Thru C C 23.2 C Right A Left D D Right B TH 22 and TH 14 South Ramps Northbound Southbound Eastbound Thru A A Right A Left F C 14.4 B Thru B Left D B Right A TH 22 and Adams Street Left C Northbound Thru C 18.6 C Right A Left C Southbound Thru C 17.7 C Right A C Left D Eastbound Thru E 30.9 D Right B Left C Westbound Thru B 7.3 A Right A

95 TH 22 VISSIM Analysis MnDOT District 7 _2030_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Madison Avenue Left B Northbound Thru B 11.2 B Right A Left B Southbound Thru A 7.7 A Right A B Left C Eastbound Thru B 12.5 B Right A Left C Westbound Thru B 13.4 B Right A TH 22 and Bassett Drive Left A Northbound Thru A 5.8 A Right A Left B Southbound Thru B 10.4 B Right A A Left B Eastbound Thru B 6.7 A Right A Left A Westbound Thru A 5.6 A Right A TH 22 and Hoffman Road Left A Northbound Thru A 3.2 A Right A Left A Southbound Thru A 4.1 A Right A A Left D Eastbound Thru B 21.6 C Right A Left B Westbound Thru A 6.8 A Right A Adams Street and Haefner Drive Left A Northbound Thru A 4.1 A Right A Left A Southbound Thru A 3.4 A Right A A Left A Eastbound Thru A 2.4 A Right A Left A Westbound Thru A 5.4 A Right A Madison Avenue and Haefner Drive Left A Northbound Thru A 4.9 A Right A Left A Southbound Thru A 3.1 A Right A A Left A Eastbound Thru A 2.3 A Right A Left A Westbound Thru A 3.3 A Right A

96 TH 22 VISSIM Analysis MnDOT District 7 _2030_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 VISSIM Network Results _2030_Roundabouts_24 hours 2x2 Avg Delay (s) Avg Speed TRAVTMTOT DELAYTOT DEMAND Vehicles Distance (mi) (MPH) (ALL) (ALL) LATENT Avg St Dev VISSIM Travel Time Results _2030_Roundabouts_24 hours 2x2 Travel Times NB TH 22 to NB TH 22 NB TH 22 to US Hwy 14 SB TH 22 to SB TH 22 SB TH 22 to US Hwy 14 Run # 1 Run # 2 Run # 3 Run # 4 Run # 5 AVG #REF! #REF! 178.8

97 TH 22 VISSIM Analysis MnDOT District 7 _2045_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Blue Earth CSAH 26 Left D Northbound Thru B 19.7 B Right A Left A Southbound Thru C 24.0 C Right A C Left D Eastbound Thru D 17.2 B Right A Left D Westbound Thru D 35.3 D Right A TH 22 and Augusta Drive Left D Northbound Thru B 22.0 C Right A Left D Southbound Thru D 34.9 C Right B C Left D Eastbound Thru C 22.3 C Right A Left C Westbound Thru D 29.3 C Right A TH 22 and North Victory Drive Left D Northbound Thru C 33.0 C Right A Left E Southbound Thru C 31.0 C Right B C Left E Eastbound Thru D 38.9 D Right B Left D Westbound Thru D 43.0 D Right A TH 22 and TH 14 North Ramps Northbound Southbound Westbound Left C A Thru A Thru D D 28.3 C Right A Left D D Right B TH 22 and TH 14 South Ramps Northbound Southbound Eastbound Thru A A Right A Left F B 13.3 B Thru B Left D B Right A TH 22 and Adams Street Left F Northbound Thru C 46.0 D Right B Left C Southbound Thru B 18.0 B Right A C Left D Eastbound Thru D 38.4 D Right B Left D Westbound Thru E 28.9 C Right A

98 TH 22 VISSIM Analysis MnDOT District 7 _2045_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Madison Avenue Left D Northbound Thru B 17.9 B Right A Left E Southbound Thru E 52.1 D Right C D Left D Eastbound Thru D 32.6 C Right B Left C Westbound Thru D 36.5 D Right A TH 22 and Bassett Drive Left E Northbound Thru C 32.4 C Right A Left E Southbound Thru D 47.4 D Right B D Left C Eastbound Thru D 28.6 C Right B Left E Westbound Thru D 41.0 D Right B TH 22 and Hoffman Road Left E Northbound Thru C 27.2 C Right A Left E Southbound Thru D 36.3 D Right A C Left D Eastbound Thru D 45.3 D Right A Left D Westbound Thru D 33.3 C Right B Adams Street and Haefner Drive Left A Northbound Thru A 6.1 A Right A Left A Southbound Thru A 4.5 A Right A A Left A Eastbound Thru A 6.0 A Right A Left A Westbound Thru A 8.8 A Right B Madison Avenue and Haefner Drive Left B Northbound Thru A 9.6 A Right A Left A Southbound Thru A 3.6 A Right A A Left A Eastbound Thru A 5.1 A Right A Left A Westbound Thru A 5.0 A Right A

99 TH 22 VISSIM Analysis MnDOT District 7 _2045_Build Traffic Signals_24 Hours VISSIM Arterial MOE Results Start Time: 16:00 VISSIM Network Results _2045_Build Traffic Signals_24 Hours Avg Delay (s) Avg Speed TRAVTMTOT DELAYTOT DEMAND Vehicles Distance (mi) (MPH) (ALL) (ALL) LATENT Avg St Dev VISSIM Travel Time Results _2045_Build Traffic Signals_24 Hours Travel Times NB TH 22 to NB TH 22 NB TH 22 to US Hwy 14 SB TH 22 to SB TH 22 SB TH 22 to US Hwy 14 Run # 1 Run # 2 Run # 3 Run # 4 Run # 5 AVG

100 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Blue Earth CSAH 26 Left A Northbound Thru A 3.6 A Right A Left A Southbound Thru B 10.6 B Right A A Left A Eastbound Thru A 8.0 A Right A Left C Westbound Thru D 25.9 D Right A TH 22 and Augusta Drive Left A Northbound Thru A 6.2 A Right A Left A Southbound Thru A 6.9 A Right A F Left F Eastbound Thru F F Right F Left F Westbound Thru F F Right F TH 22 and North Victory Drive Left B Northbound Thru A 8.2 A Right A Left E Southbound Thru E 37.8 E Right C D Left E Eastbound Thru C 24.0 C Right B Left F Westbound Thru E 55.2 F Right A TH 22 and TH 14 North Ramps Northbound Southbound Westbound Left C B Thru A Thru D C 24.0 C Right A Left D D Right B TH 22 and TH 14 South Ramps Northbound Southbound Eastbound Thru B A Right A Left E C 14.5 B Thru B Left E B Right A TH 22 and Adams Street Left D Northbound Thru D 31.3 D Right B Left D Southbound Thru D 21.6 C Right A F Left F Eastbound Thru F F Right F Left F Westbound Thru F F Right F

101 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Madison Avenue Left F Northbound Thru E 44.4 E Right B Left B Southbound Thru A 8.5 A Right A F Left F Eastbound Thru F F Right F Left F Westbound Thru F F Right E TH 22 and Bassett Drive Left B Northbound Thru B 10.4 B Right A Left D Southbound Thru C 24.5 C Right B C Left C Eastbound Thru C 10.1 B Right A Left D Westbound Thru C 17.2 C Right A TH 22 and Hoffman Road Left A Northbound Thru A 4.1 A Right A Left B Southbound Thru A 8.7 A Right A D Left F Eastbound Thru F F Right B Left F Westbound Thru D 27.6 D Right A Adams Street and Haefner Drive Left F Northbound Thru F F Right E Left F Southbound Thru F 91.8 F Right F F Left D Eastbound Thru A 14.7 B Right A Left F Westbound Thru F F Right F Madison Avenue and Haefner Drive Left E Northbound Thru B 25.6 D Right A Left E Southbound Thru E 34.9 D Right D C Left A Eastbound Thru A 3.2 A Right A Left C Westbound Thru D 22.8 C Right A

102 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 VISSIM Network Results _2045_Roundabouts_24 hours 2x2 Avg Delay (s) Avg Speed TRAVTMTOT DELAYTOT DEMAND Vehicles Distance (mi) (MPH) (ALL) (ALL) LATENT Avg St Dev VISSIM Travel Time Results _2045_Roundabouts_24 hours 2x2 Travel Times NB TH 22 to NB TH 22 NB TH 22 to US Hwy 14 SB TH 22 to SB TH 22 SB TH 22 to US Hwy 14 Run # 1 Run # 2 Run # 3 Run # 4 Run # 5 AVG #REF! #REF!

103 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts Metered_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Blue Earth CSAH 26 Left A Northbound Thru A 4.5 A Right A Left A Southbound Thru B 11.3 B Right B A Left A Eastbound Thru A 8.2 A Right A Left D Westbound Thru E 33.9 D Right A TH 22 and Augusta Drive Left B Northbound Thru A 9.2 A Right A Left A Southbound Thru B 11.1 B Right A D Left F Eastbound Thru E 70.5 F Right E Left F Westbound Thru C 73.1 F Right D TH 22 and North Victory Drive Left C Northbound Thru B 12.6 B Right A Left E Southbound Thru E 41.2 E Right C C Left C Eastbound Thru A 11.0 B Right A Left D Westbound Thru C 21.0 C Right A TH 22 and TH 14 North Ramps Northbound Southbound Westbound Left D B Thru A Thru D D 26.5 C Right A Left D D Right B TH 22 and TH 14 South Ramps Northbound Southbound Eastbound Thru B A Right A Left F C 14.2 B Thru B Left E B Right A TH 22 and Adams Street Left E Northbound Thru E 37.2 E Right B Left D Southbound Thru D 23.2 C Right A E Left F Eastbound Thru F 55.3 F Right E Left F Westbound Thru F 82.1 F Right D

104 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts Metered_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 TH 22 and Madison Avenue Left F Northbound Thru F 54.0 F Right B Left D Southbound Thru C 19.8 C Right A E Left E Eastbound Thru C 29.3 D Right B Left F Westbound Thru F 50.7 F Right B TH 22 and Bassett Drive Left B Northbound Thru B 11.7 B Right A Left D Southbound Thru D 25.8 D Right B C Left C Eastbound Thru C 10.1 B Right A Left C Westbound Thru B 12.5 B Right A TH 22 and Hoffman Road Left A Northbound Thru A 8.7 A Right A Left C Southbound Thru C 16.4 C Right A C Left F Eastbound Thru E 46.2 E Right A Left D Westbound Thru C 14.3 B Right A Adams Street and Haefner Drive Left E Northbound Thru C 23.2 C Right A Left F Southbound Thru F F Right F E Left B Eastbound Thru A 6.5 A Right A Left F Westbound Thru F 86.6 F Right F Madison Avenue and Haefner Drive Left B Northbound Thru A 9.0 A Right A Left A Southbound Thru A 5.6 A Right A A Left A Eastbound Thru A 2.8 A Right A Left A Westbound Thru A 6.3 A Right A

105 TH 22 VISSIM Analysis MnDOT District 7 _2045_Roundabouts Metered_24 hours 2x2 VISSIM Arterial MOE Results Start Time: 16:00 VISSIM Network Results _2045_Roundabouts Metered_24 hours 2x2 Avg Delay (s) Avg Speed TRAVTMTOT DELAYTOT DEMAND Vehicles Distance (mi) (MPH) (ALL) (ALL) LATENT Avg St Dev VISSIM Travel Time Results _2045_Roundabouts Metered_24 hours 2x2 Travel Times NB TH 22 to NB TH 22 NB TH 22 to US Hwy 14 SB TH 22 to SB TH 22 SB TH 22 to US Hwy 14 Run # 1 Run # 2 Run # 3 Run # 4 Run # 5 AVG #REF! #REF!

106 INTERSECTION CONTROL EVALUATION Trunk Highway 22 and Bassett Drive Mankato, Minnesota November 2018

107 Trunk Highway 22 and Bassett Drive Intersection Control Evaluation Mankato, Blue Earth County, Minnesota I hereby certify that this report was prepared by me or under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. Mike Bittner, PE, PTOE Date: 11/28/2018 License No: Approved: MnDOT District 7 Traffic Engineer Date MnDOT District 7 State Aid Engineer Date ICE Report TH 22 and Bassett Drive i

108 Contents Background and Study Area... 1 Roadway Characteristics... 1 Study Intersection Configuration... 1 Access Spacing... 1 Traffic Volumes... 2 Warrant Analysis... 4 Traffic Operations... 4 Existing Conditions Traffic Operations... 4 Future Conditions Traffic Operations... 4 Queue Analysis... 5 Multimodal Roundabout Considerations... 6 Truck Considerations... 6 Crash History... 6 Corridor Vision... 7 Benefit Cost Analysis... 8 Summary and Recommendation... 9 Appendices A. P.M. Peak Hour Traffic Simulation Results B. Benefit/Cost Analysis Worksheets ICE Report TH 22 and Bassett Drive ii

109 Background and Study Area As part of the Trunk Highway (TH) 22 Corridor Study, intersection control revisions are being considered at the intersection of TH 22 and Bassett Drive in Mankato. The objective of this Intersection Control Evaluation report is to determine the optimal intersection control to improve future traffic capacity and reduce crash potential. The following intersection control options were evaluated:» Traffic signal (existing control)» Multilane Roundabout with bypasses The study area can be seen in Figure 1. Roadway Characteristics TH 22 is functionally classified as a minor arterial and Bassett Drive is classified as a major collector west of TH 22 and a minor collector east of TH 22. At the intersection, TH 22 has a 45 mph posted speed limit and Bassett Drive has a posted speed limit of 30 mph. STUDY INTERSECTION CONFIGURATION The intersection is signal controlled. The lane configuration is:» Southbound: Two through lanes, dedicated right and left turn lanes» Northbound: Two through lanes, dedicated right and left turn lanes» Eastbound: One through lane, dedicated right and left turn lanes» Westbound: One through lane, dedicated right and left turn lanes ACCESS SPACING North of Bassett Drive, the closest access point is roundabout controlled CSAH 17 (Madison Avenue) which is 1,330 feet (0.25 miles) away. South of Bassett Drive, the closest access point is signal controlled Hoffman Road which is 2,600 feet (0.5 miles) away. Note that a previous Intersection Control Evaluation recommended a future roundabout at Hoffman Road. MnDOT access spacing guidelines for urban/urbanizing minor arterials (Mn/DOT Access Management Manual [2008]) recommends 1/4 mile access spacing for primary full movement intersections, and 1/8 mile access spacing for secondary intersections. Access spacing and associated access recommendations are being developed with the larger TH 22 Corridor Study. On Bassett Drive itself, there are commercial accesses within 300 feet of the intersection on both the eastbound and westbound approaches. These accesses could be converted to restricted access configurations to improve traffic flow and reduce crash potential. ICE Report TH 22 and Bassett Drive 1

110 Traffic Volumes Existing and projected average daily traffic volumes (ADT) and peak hour turning movements at the study intersection can be seen in Figure 1. Existing volumes are 2017 traffic volumes that were collected for the TH 22 Corridor Study. Traffic projections for 2030 and 2045 were developed in the corridor study through a review of historic traffic patterns and growth rates as well as expected land use changes in the area. Based on discussions with the TH 22 corridor study Technical Advisory Committee, it has been established that 2045 traffic projections documented in this report reflect an aggressive growth scenario average annual growth rates and 2030 ADT estimates were calculated from 2017 daily intersection counts and assumed 2.5 percent to the north, south, and east, and 1.4 percent to the west. As such, if less intense development occurs in the area than assumed for the 2045 traffic projections, 2030 traffic projections presented in this document could approximate 2045 projections in a more moderate growth scenario. ICE Report TH 22 and Bassett Drive 2

111 Figure 1 Study Area Details ICE Report TH 22 and Bassett Drive 3

112 Warrant Analysis Traffic signal warrants from the Minnesota Manual on Uniform Traffic Control Devices were evaluated under existing and projected traffic volumes. Minor approach right turns were omitted from this analysis given the presence of eastbound and westbound right turn lanes on Bassett Drive. It is typical for a traffic signal or roundabout to be considered for MnDOT roadways when Warrant 1 is met (Scott Thompson MnDOT D7). Under existing volumes Warrants 1, 2, and 3 are all met. Criteria Table 2 Signal Warrant Analysis (2017) Hours Met Hours Required Warrants Met Warrant 1a: Minimum Vehicular Volume 12 8 Met Warrant 1b: Interruption of Continuous Traffic 13 8 Met Warrant 2: Four Hour Vehicular Volume 12 4 Met Warrant 3: Peak Hour 12 1 Met Traffic Operations Existing Conditions Traffic Operations Intersection operations for both signal control and roundabout control were evaluated using the Vissim software. Control delay for each level of service threshold can be seen in Table 1. Per MnDOT Access Management Manual and FHWA guidance, LOS E or worse will be considered an operational deficiency where mitigation should be discussed. Table 1 Highway Capacity Manual Intersection Level of Service Thresholds Control Delay Unsignalized Signalized Level of Service (LOS) A > > B > > C > > D > > E > 50 > 80 F Under existing traffic volumes, intersection geometry, and signal control, the intersection operates at LOS C during both the AM and PM peak hours, with no approach operating worse than LOS C. The existing signalized intersection would benefit from connection/interoperability of traffic signals throughout the corridor. Future Conditions Traffic Operations Vissim models were developed for a 24 hour time period under projected 2030 and 2045 traffic volumes. Roundabout simulation assumes a multilane roundabout at Bassett Drive, with right turn bypass lanes on all intersection approaches. Bypass lanes were assumed in both 2030 and 2045 simulations since modelled operations without them resulted in major delays and queue spillback issues. Simulation results indicate that a roundabout will operate with less control delay than a traffic signal during all hours of the day under both 2030 and 2045 traffic conditions. Configurations for both future alternatives can be seen in Table 7 at the end of this report. ICE Report TH 22 and Bassett Drive 4

113 In 2030, a roundabout is expected to operate with less than 10 seconds of control delay per vehicle throughout the day, while a signal is expected to operate with over 25 seconds of control delay between 8 am and 7 pm, with delays approaching 35 seconds per vehicle during the PM peak hour. Under 2045 traffic volumes, roundabout control delay is expected to be under 15 seconds of delay per vehicle throughout most of the day, however delays increase in the PM peak hour to around 30 seconds per vehicle. Signal control is expected to have delays of over 30 seconds per vehicle between 8 am and 7 pm, with PM peak delays approaching 50 seconds per vehicle under 2045 conditions. As part of a larger network wide modelling effort the impact that placing meters on roundabout approaches to assign right of way was studied for 2045 conditions, but it was found to have negligible impacts at the study intersection. As such, subsequent analysis presented in this ICE report assumes no roundabout metering is present. Figure and 2045 Modelled Intersection Delays at Bassett Drive Note: LOS thresholds on this graphic are for unsignalized intersection Table 3 Average Control Delays (24 hour Average) at Bassett Drive Traffic Control 2030 Average Delay (24 Hour 2045 Average Delay (24 Hour Average) Average) Traffic Signal 20.5 seconds 22.9 seconds Roundabout 3.2 seconds 5.7 seconds P.M. peak hour traffic operations by approach for each traffic control option can be seen in Appendix A. Queue Analysis Average PM peak hour simulated queue lengths were evaluated. Average queue lengths are expected to be reduced with roundabout control on all approaches under both 2030 and 2045 conditions. Table 4 Average 2030 and 2045 Queue Lengths at Bassett Drive Approach Signal* Roundabout Signal* Roundabout Northbound Southbound Eastbound Westbound Queue lengths shown in feet *Reflects longest average queue on each approach under signal control ICE Report TH 22 and Bassett Drive 5

114 Multimodal Roundabout Considerations Reduced vehicle speeds associated with roundabout control allow more time for drivers and pedestrians to interact with each other, and the presence of raised splitter islands also simplifies the task of pedestrian crossings by allowing pedestrians to consider one direction of conflicting traffic at a time. On street bicycle facilities are not in place nor are they planned, so most cyclists will use a roundabout like pedestrians. Note that pedestrian crossings are being evaluated on a corridor level as part of the TH 22 corridor study, with recommendations being made related to potential dedicated pedestrian crossings at appropriate locations. Truck Considerations Roundabouts have been successfully constructed on many Minnesota trunk highways, including two on the TH 22 corridor at Adams Street and Madison Avenue. With proper roundabout design characteristics such as a sufficient inscribed circle diameter and truck aprons with curbs designed to prevent load shifting, trucks can navigate roundabouts without issue. Information from MnDOT s Right of Way Mapping and Monitoring web application indicates approximately 210 feet of right of way at Bassett Drive, with MnDOT recommending roundabout diameters (MnDOT Road Design Manual Table A [2009]) of 150 to 200 feet for urban two lane roundabouts. Crash History Crash data was obtained from MnDOT for the time period between January 2011 and December In the fiveyear period, 46 crashes were reported. Three crashes resulted in non incapacitating injuries and six crashes resulted in possible injuries. The crash distribution is as follows:» 21 rear end» 9 right angle» 6 sideswipe» 3 run off the road» 2 left turn» 1 right turn» 4 other (not specified) Using the critical crash analysis methodology which applies statistical analysis to determine if the difference in observed and typical crash rates is statistically significant, the intersection crash rate is above the critical crash rate. As such, the existing intersection configuration is likely contributing to the elevated crash rates that have been observed. To evaluate the expected safety impact from conversion from signal control to roundabout control, the FHWA Surrogate Safety Assessment Model (SSAM) was used. The SSAM uses vehicle trajectory information from Vissim simulation models to identify the number of rear end, lane change, and crossing conflicts. Simulation results from a full 24 hour Vissim model were used for this analysis. Under 2030 traffic volumes and roundabout control, the total number of conflicts is expected to be reduced by 14 percent and rear end conflicts are expected to be reduced by 25 percent compared to a traffic signal. Due to increased congestion under roundabout control by 2045, a 12 percent increase in the total number of conflicts is expected in 2045, with rear end conflicts being comparable to signal control. Roundabout control however results in more predictable rear end conflicts since there is no yellow signal phase that can cause drivers to abruptly stop. Lane change conflicts are expected to increase significantly under both 2030 and 2045 volumes, however these conflicts have a low potential to be severe. Reducing the crossing conflict rate is the biggest indicator of reducing severe crashes. MnDOT data in the Traffic Safety Fundamentals Handbook (2015) indicates a 60 to 70 percent reduction in severe crashes (injury or fatal crashes) with a multilane roundabout compared to a signal. ICE Report TH 22 and Bassett Drive 6

115 Table 5 Conflict Comparison Between Traffic Signal and Roundabout Alternative Rear End Conflicts Lane Change Crossing Total Rear End Signal Roundabout % Chg. W/ Roundabout 25% 63% 26% 14% 1% 120% 28% 12% Note: Roundabout conflicts were evaluated with no roundabout metering Corridor Vision Throughout the TH 22 corridor study, it has been established that the future vision for the TH 22 corridor through urbanized Mankato is a roundabout corridor. As part of a larger traffic simulation effort as part of the corridor study it was found that corridor wide operations (CSAH 26 to Hoffman Road) are improved with a roundabout corridor compared to a signal corridor (see Figure 3 and Figure 4). Under 2030 traffic conditions, network wide delay is lower with a roundabout corridor for every hour of the day, and under 2045 conditions roundabout operations are better than signal operations for most of the day except between 3 pm and 7 pm. Metered roundabouts can however be used in the future at congested locations, and simulation results indicate operations much closer to a signal corridor in 2045 if metering is used, however delays still are expected to exceed signal operations between 4 pm and 6 pm. More specific details related to the corridor wide modelling effort and results can be seen in the Vissim Urban Analysis Report which is part of the TH 22 Corridor Study. Figure Network Delay Comparison Lane Change Crossing Total ICE Report TH 22 and Bassett Drive 7

116 Figure Network Delay Comparison Benefit Cost Analysis Benefit Cost Analysis (BCA) provides an indication of the economic desirability of an alternative, by comparing the benefits along with the assessment of other effects and impacts. Projects are considered cost effective if the benefitcost ratio is greater than 1.0. The larger the ratio number, the greater the benefits per unit cost. A BCA was performed for the roundabout alternative compared to the existing traffic signal control. The analysis was based on MnDOT Benefit Cost Analysis Guidelines (SFY2019) to compare to similar projects throughout the region. Vehicle miles traveled (VMT), vehicle hours traveled (VHT), and crash reduction savings were quantified to show operational and safety benefits. Construction costs, maintenance costs, and remaining capitol value were quantified to represent the total user costs for the project. The benefits and costs of each alternative were compared for a 20 year timeframe assumed between Based on the actual construction year, these results may increase or decrease slightly from the assumptions used for the current analysis. For the purposes of this ICE report, economic desirability of the concept was compared between intersection alternatives. Table 6 shows a summary of the BCA results for the roundabout alternative versus the existing traffic signal. The roundabout shows a very high operational benefit even with deceleration time approaching the roundabout added into the control delay. Combined with the safety benefit, a roundabout is a very economically desirable alternative compared to the existing signal for the next 20 years. Table 6 20 Year BCA Analysis Results Roundabout Net Cost of Project ($M) $0.94 Present Value of Benefits ($M) $9.04 Net Present Value ($M) $8.10 Benefit / Cost Ratio 9.58 ICE Report TH 22 and Bassett Drive 8

117 Summary and Recommendation A multilane roundabout is expected to operate with fewer delays than a traffic signal for all hours of the day through 2045 (see Figure 2). Intersection conflicts are expected to be reduced with roundabout control through 2030, however roundabout conflicts are expected to exceed signal conflicts by While total 2045 roundabout conflicts may be higher than signal conflicts, roundabouts reduce the potential for severe crashes and also result in more predictable rear end type conflicts given the removal of a yellow signal phase that can cause drivers to abruptly stop. The future construction of a roundabout will align with the future corridor vision of a roundabout corridor, is consistent with recently constructed roundabouts at both Adams Street and Madison Avenue, is economically desirable, and can fit within available right of way. Based on analysis presented in this report, a multilane roundabout with bypass lanes is recommended at the intersection of TH 22 and Bassett Drive. Table 7 Summary of Analysis ICE Report TH 22 and Bassett Drive 9