AASHTO Policy on Geometric Design of Highways and Streets 2001 Highlights and Major Changes Since the 1994 Edition Jim Mills, P.E. Roadway Design Office 605 Suwannee Street MS-32 Tallahassee, FL 32399-0450 850-414-4318 SC 994-4318 jim.mills@dot.state.fl.us FACERS Annual Conference - June 26-29, 2002 1
Implementation FHWA Adoption NHS Highways March 14, 2002 States will have 1 year following FHWA Adoption to Begin Using (March 14, 2003) FDOT will use this time to review and make any necessary changes to FDOT Design Criteria and Update the PPM Florida Greenbook Update for 2004? FACERS Annual Conference - June 26-29, 2002 2
Implementation For Now on FDOT Projects PPM & 94 AASHTO In Effect Exceptions are to be based on 94 AASHTO until 2001 Edition is recognized in PPM 2001 Edition may be used as support when documenting, justifying Design Exceptions January 2003 PPM will incorporate 01 AASHTO FACERS Annual Conference - June 26-29, 2002 3
Development Developed by the AASHTO Task Force on Geometric Design, including representatives from: 18 State Departments of Transportation Federal Highway Administration American Public Works Association National Association of County Engineers National League of Cities Port Authority of NY and NJ FACERS Annual Conference - June 26-29, 2002 4
Format 8.5-in x 11-in pages with soft cover Sequence of chapters unchanged Chapter numbers are arabic rather than Roman numerals Figures and tables are uniformly called exhibits and are numbered sequentially in each chapter to reduce confusion in referencing FACERS Annual Conference - June 26-29, 2002 5
Units of Measurement Both metric and U.S. customary units are used In Text Metric first, followed by U.S. customary in square brackets: 80 km/h [50 mph] In Exhibits Separate exhibits for metric and U.S. customary units are presented where needed FACERS Annual Conference - June 26-29, 2002 6
Units of Measurement Metric values are those that would be used if the policy were entirely metric U.S. customary values are those that would be used if the policy were entirely U.S. customary Users should work entirely in one system of measurement or the other Do not attempt to convert values! FACERS Annual Conference - June 26-29, 2002 7
Research 2001 Green Book based on latest research projects, including: NCHRP 375 Median Intersection Design NCHRP 383 Intersection Sight Distance NCHRP 400 Stopping Sight Distance NCHRP 420 Access Management NCHRP 439 Superelevation and Transitions Highway Capacity Manual 2000 FACERS Annual Conference - June 26-29, 2002 8
Additional Research Also: NCHRP 240 Toll Plazas NCHRP 241 Truck Operating Characteristics NCHRP 264 Roundabouts Transportation Research Circular 430 FHWA-RD-97-135 Older Driver Handbook FHWA-RD-00-067 Roundabouts: An Informational Guide FACERS Annual Conference - June 26-29, 2002 9
Chapter 1 Highway Functions No major changes FACERS Annual Conference - June 26-29, 2002 10
Chapter 2 Design Controls and Criteria New design speed definition a selected speed used to determine the various geometric design features of the roadway. should be logical with respect to topography, anticipated operating speed, adjacent land use, and functional classification. Old design speed definition...maximum safe speed that can be maintained over a specific section of highway when conditions are so favorable that the design features of the highway govern. (Same wording used in Florida Greenbook) FACERS Annual Conference - June 26-29, 2002 11
Chapter 2 Design Controls and Criteria Revised design vehicle dimensions to better reflect the existing fleet New design vehicle turning templates Additional information on access control and access management, older drivers, and pedestrians Corresponding design speeds in metric and U.S. customary units are specified FACERS Annual Conference - June 26-29, 2002 12
Chapter 2 Design Controls and Criteria Revised Dimensions for Selected Design Vehicles 90 AASHTO and FGB P SU WB 50 01 AASHTO 90 AASHTO and FGB 01 AASHTO 90 AASHTO and FGB 01 AASHTO Height 4.25 4.25 13.5 11-13.5 13.5 13.5 Width 7 7 8.5 8 8.5 8.5 Length 19 19 30 30 55 55 Front Overhang 3 3 4 4 3 3 Rear Overhang 5 5 6 6 2 2 WB 1 11 11 20 20 20 14.6 WB 2 30 35.4 Min Turning Radius 24 24 42 42 45 45 Min Inside Radius 13.8 14.4 24.4 28.3 19.2 17 FACERS Annual Conference - June 26-29, 2002 13
Chapter 3 Elements of Design Extends range of design speeds considered 20 to 130 km/h [15 to 80 mph] Incorporates superelevation criteria and updates transitions and spirals based on research in NCHRP Report 439 Charts for critical length of grade based on a 120 kg/kw [200 lb/hp] truck, rather than a 180 kg/kw [300 lb/hp] truck FACERS Annual Conference - June 26-29, 2002 14
Chapter 3 Elements of Design Revised Turning Roadway Widths based on Updated Design Vehicle Dimensions FACERS Annual Conference - June 26-29, 2002 15
Design Widths for Turning Roadways (feet) RADIUS To Inside of Curve Traveled Way Width 1-LANE Case I-C 90 AASHTO and FGB 01 AASHTO 50 23 23 75 19 20 100 18 18 150 17 17 200 16 16 300 16 15 400 16 15 500 15 15 Tangent 15 14 FACERS Annual Conference - June 26-29, 2002 16
Design Widths for Turning Roadways (feet) RADIUS To Inside of Curve Traveled Way Width 1-LANE Case II - B Provision for Passing Stalled Vehicle 90 AASHTO and FGB 01 AASHTO 50 25 26 75 23 23 100 22 22 150 21 21 200 21 20 300 20 20 400 20 19 500 20 19 Tangent 19 18 FACERS Annual Conference - June 26-29, 2002 17
Design Widths for Turning Roadways (feet) Traveled Way Width RADIUS To 2-LANE Case III-A Inside of Includes 2' deduction for shoulder. Curve 90 AASHTO 01 AASHTO and FGB 50 29 29 75 27 27 100 26 26 150 25 24 200 25 24 300 24 24 400 24 24 500 24 24 Tangent 24 24 FACERS Annual Conference - June 26-29, 2002 18
Chapter 3 Elements of Design Stopping Sight Distance Criteria revised based on NCHRP Report 400 initial speed equal to design speed (no reduction to average running speed) based on deceleration rates for controlled braking rather than locked-wheel braking deceleration rate is 3.4 m/s 2 [11.2 ft/s 2 ], independent of speed FACERS Annual Conference - June 26-29, 2002 19
Chapter 3 Elements of Design Design Speed 90 AASHTO lower (FGB) upper 15 80 20 125 125 115 25 150 150 155 Interstate Other Arterials Collectors A B C 30 200 200 200 200 200 200 165 35 225 250 250 250 225 240 220 200 40 275 325 305 300 275 300 270 240 45 325 400 360 375 350 325 350 325 280 50 400 475 425 450 400 400 410 400 325 55 450 550 495 550 500 475 450 470 450 370 60 525 650 570 625 575 550 500 530 525 420 65 550 725 645 700 625 600 610 550 455 70 625 850 730 800 725 700 690 625 520 75 820 80 910 Stopping Sight Distance 01 AASHTO Freeways FDOT Plans Preparation Manual New/Reconstr FACERS Annual Conference - June 26-29, 2002 20 RRR
Stopping Sight Distance Stopping Sight Distance - Feet 1000 900 800 700 600 500 400 300 200 100 0 90 AASHTO lower 01 AASHTO PPM Freeways Interstate PPM New/Reconstr Arterials PPM RRR C 0 10 20 30 40 50 60 70 80 90 Design Speed - mph FACERS Annual Conference - June 26-29, 2002 21
Chapter 3 Elements of Design Vertical Curve Design Criteria revised based on NCHRP Report 400 driver eye height: 1,080 mm [3.5 ft], rather than 1,070 mm [3.5 ft] object height: 600 mm [2.0 ft], which represents vehicle tail light height, rather than 150 mm [6 in], which represented an arbitrary object height Improved discussion of sight distance at undercrossings FACERS Annual Conference - June 26-29, 2002 22
Vertical Curve Design Criteria Eye Height 90 AASHTO/FGB = 3.5 01 AASHTO = 3.5 Object Height 90 AASHTO/FGB = 6 01 AASHTO = 2.0 FACERS Annual Conference - June 26-29, 2002 23
Design Speed lower FGB upper 15 3 20 10 10 7 25 20 20 12 Interstate Other Arterials Collectors A B C 30 30 30 19 30 30 30 30 20 35 40 50 29 50 40 43 36 30 40 60 80 44 70 60 68 55 43 45 80 120 61 110 90 80 92 79 59 50 110 120 160 84 150 130 120 126 120 79 55 150 220 114 220 190 170 150 166 152 103 60 190 310 151 300 250 230 190 211 207 133 65 230 400 193 380 320 280 230 280 228 156 70 290 540 247 500 400 370 358 294 203 75 312 80 384 K Value - Crest Vertical Curves 90 AASHTO PPM 01 AASHTO Freeways New and Reconstr RRR FACERS Annual Conference - June 26-29, 2002 24
K Value - Crest Vertical Curves 600 90 AASHTO lower 500 01 AASHTO K-Value - Crest Vert Curves 400 300 200 PPM Freeways Interstate PPM New and Reconstr Arterials PPM RRR C 100 0 0 10 20 30 40 50 60 70 80 90 Design Speed - mph FACERS Annual Conference - June 26-29, 2002 25
Design Speed lower (FGB) upper 01 AASHTO 15 10 20 20 20 17 25 30 30 26 Interstate Other Arterials Collectors A B C 30 40 40 37 40 40 36 36 28 35 50 50 49 50 50 46 41 36 40 60 70 64 60 60 62 54 46 45 70 90 79 80 80 70 75 69 57 50 90 110 96 100 90 90 92 89 69 55 100 130 115 130 120 110 100 108 103 81 60 120 160 136 150 140 130 120 125 123 94 65 130 180 157 170 160 150 130 147 130 104 70 150 220 181 200 180 170 169 151 122 75 206 80 231 K Value - Sag Vertical Curves 90 AASHTO PPM Freeways New and Reconstr RRR FACERS Annual Conference - June 26-29, 2002 26
K Value - Sag Vertical Curves 250 90 AASHTO lower K Value - Sag Vert Curves 200 150 100 01 AASHTO PPM Freeways Interstate PPM New and Reconstr Arterials PPM RRR C 50 0 0 10 20 30 40 50 60 70 80 90 Design Speed mph FACERS Annual Conference - June 26-29, 2002 27
Chapter 4 Cross Section Elements Curb terminology changed vertical curb replaces barrier curb sloping curb replaces mountable curb NOTE: FDOT Type F and Type E curb meet the AASHTO definition for Sloping Curb. FACERS Annual Conference - June 26-29, 2002 28
Chapter 4 Cross Section Elements Eliminates material on parabolic cross sections Discusses sidewalk curb ramps and ADA compliance Incorporates research on median width and median opening design from NCHRP Report 375 FACERS Annual Conference - June 26-29, 2002 29
Chapter 5 Local Roads and Streets Includes discussions of: ADA compliance new AASHTO bicycle guide proposed AASHTO pedestrian guide (currently in preparation) Refers to forthcoming AASHTO report Guidelines for Geometric Design of Very Low Volume Local Roads (< 400 ADT) FACERS Annual Conference - June 26-29, 2002 30
Chapter 6 Collector Roads and Streets Includes discussions of: ADA compliance new AASHTO bicycle guide proposed AASHTO pedestrian guide Eliminates material on parabolic cross sections FACERS Annual Conference - June 26-29, 2002 31
Chapter 6 Collector Roads and Streets Incorporates research on median width and median opening design from NCHRP Report 375 Incorporates revised discussions of: traffic control devices erosion control FACERS Annual Conference - June 26-29, 2002 32
Chapter 7 Rural and Urban Arterials Incorporates research on median width and median opening design from NCHRP Report 375 Incorporates research on access management from NCHRP Report 420 Places more emphasis on design to accommodate pedestrians and bicycles in the arterial environment FACERS Annual Conference - June 26-29, 2002 33
Chapter 8 Freeways No major changes FACERS Annual Conference - June 26-29, 2002 34
Chapter 9 Intersections Chapter title changed from At-Grade Intersections Explicitly defines the functional area of an intersection includes the distance a vehicle travels during perception-reaction and maneuvering (braking and lane changing), and the space needed for storage (to accommodate the longest queue expected most often) FACERS Annual Conference - June 26-29, 2002 35
Chapter 9 Intersections Includes discussions of: access management near intersections modern roundabouts Includes expanded discussion of offset left-turn lanes advantages include better visibility, reduced conflicts and the ability to serve more vehicles. FACERS Annual Conference - June 26-29, 2002 36
Chapter 9 Intersections Includes revised intersection sight distance criteria based on NCHRP Report 383 revised criteria for uncontrolled intersections new gap acceptance criteria for entering or crossing major roads limited sight distances for signals and all-way stops FACERS Annual Conference - June 26-29, 2002 37
Intersection Sight Distance Length of SD Leg Along Major Road Length of SD Leg Along Major Road Major Road Sight Line a = driver eye setback 1990 AASHTO: a = 20 Florida Greenbook: a = 15 2001 AASHTO: a = 17.8' desirable a = 14.4' minimum a Minor Road Sight Line FACERS Annual Conference - June 26-29, 2002 38
Design Speed Length of Sight Distance Leg along Major Road Index 546 and 90 01 AASHTO - 2 Lane Intersection - AASHT O Left and Right Turn Florida Greenbook W = 50' - based on Crossing Maneuver Left Turn Maneuver Right Turn & Crossing Maneuver 15 170 145 20 225 195 25 280 240 30 380 300 335 290 35 470 350 390 335 40 580 400 445 385 45 710 450 500 430 50 840 500 555 480 55 990 550 610 530 60 1150 600 665 575 65 1350 650 720 625 70 700 775 670 75 830 720 80 885 765 FACERS Annual Conference - June 26-29, 2002 39
Intersection Sight Distance Length of Sight Distance Leg Feet 1600 1400 1200 1000 800 600 400 200 Index 546 and 90 AASHTO Florida Greenbook W = 50' - based on Crossing Maneuver 01 AASHTO - 2 Lane Intersection - Left Turn Maneuver 01 AASHTO - 2 Lane Intersection - Right Turn & Crossing Maneuver 0 0 10 20 30 40 50 60 70 80 90 Design Speed - mph FACERS Annual Conference - June 26-29, 2002 40
Chapter 10 Grade Separations and Interchanges Places more emphasis on design to accommodate pedestrians and bicycles at interchanges Includes expanded discussion of Single Point Urban Interchanges (SPUIs) Increases emphasis on access management on interchange crossroads FACERS Annual Conference - June 26-29, 2002 41
Chapter 10 Grade Separations and Interchanges Expands discussion of superelevation and cross slope within interchanges Addresses two-lane entrance ramps FACERS Annual Conference - June 26-29, 2002 42
AASHTO Policy on Geometric Design of Highways and Streets 2001 Where to Get Copies: AASHTO P.O. Box 96716 Washington, DC 20090-6716 Phone 1-800-231-3475 Fax 1-800-525-5562 Online www.transportation.org Not available from FDOT FACERS Annual Conference - June 26-29, 2002 43
AASHTO Policy on Geometric Design of Highways and Streets 2001 Price as of June 20, 2002 BOOK ITEM NO. GDHS-4 Price per copy $102 AASHTO Members $80 CD-ROM ITEM NO. GDHS-4-CD Price per copy $165 AASHTO Members $130 BOOK & CD-ROM ITEM NO. GDHS-4-COM Price per copy $248 AASHTO Members $195 FACERS Annual Conference - June 26-29, 2002 44
AASHTO Guidelines for Geometric Design of Very Low-Volume Local Roads (ADT<400) Price as of June 20, 2002 BOOK ITEM NO. VLVLR-1 Price per copy $35.00 AASHTO Members $30.00 NACE Members may purchase at AASHTO Member price. (Must indicate membership when ordering.) FACERS Annual Conference - June 26-29, 2002 45
Florida Green Book - May 2002 Adopted by Rule Effective July 9, 2002 Includes new chapters on traffic calming and residential street design Full Document posted on the FDOT Roadway Design Office Web Site http://www11.myflorida.com/rddesign/ Hardcopies to be available in about 30 days. FACERS Annual Conference - June 26-29, 2002 46
QUESTIONS? Jim Mills, P.E. Roadway Design Office 605 Suwannee Street MS-32 Tallahassee, FL 32399-0450 850-414-4318 SC 994-4318 jim.mills@dot.state.fl.us FACERS Annual Conference - June 26-29, 2002 47