ARE DIAMONDS LRT S BEST FRIEND? AT-GRADE LRT CROSSING AT A DIAMOND INTERCHANGE

Transcription

1 ARE DIAMONDS LRT S BEST FRIEND? AT-GRADE LRT CROSSING AT A DIAMOND INTERCHANGE NATE LARSON HDR SEATTLE, WA ABHISHEK DAYAL VALLEY METRO PHOENIX, AZ ITE WESTERN DISTRICT ANNUAL MEETING JULY 16, 2013

2 Presentation Roadmap Background The Diamond Key Assumptions Early Analysis Simulation Recommendations Bonus Material

3 LRT System Plan

4 Capitol/I-10 West Extension Locally Preferred Alternative Adopted in July 2012

5 2035 Average Traffic Volumes

6 The Diamond Representative Interchange Project Committee: Valley Metro, City of Phoenix, ADOT, MAG 4 Interchanges, similar characteristics Avoid unnecessary study

7 The Diamond Representative Interchange 51 st Avenue Daily entering traffic volume Average p.m. peak hour vehicle delay Heavy truck activity North-south continuity

8 Capitol/I-10 West Extension Preliminary Station Sites Traffic Study Location

9 The Diamond

10 Key Assumptions No new lanes on 51 st Avenue LRT station starter signals No gates Only protected movements allowed across LRT tracks LRT replaces Phase 2 when present

11 Key Assumptions LRT replaces Phase 2 when present

12 Proposed Phasing

13 Proposed Phasing

14 Proposed Phasing

15 Proposed Phasing

16 Early Analysis 10-min. headway + 90-sec. cycle = 13% of total NB through capacity PM Peak Hour Data: Grade-Separated At-Grade Phase 1 Duration 32 seconds 32 seconds Phase 2 Duration 24 seconds 24 seconds Volume/Lanes 1500 vehicles * /3 Lanes 1500 vehicles * /3 Lanes Movement Capacity 4,803 veh/hr. of green 4,183 veh/hr. of green Movement LOS (Delay) A (2.5 sec/veh) A (4.4 sec/veh) * Includes portion of Northbound through volume that is served in Phase 1

17 Early Analysis NB through: delay up 75% (!), but still LOS A Committee recommended VISSIM: Implications of LOS failure Potential truck under-count Impacts due to increased pedestrian activity Availability of I-10 model

18 Simulation VISSIM analysis added: 2035 traffic volumes AM peak hour analysis Adjacent intersections Overall intersection focus (not just NB through)

19 Simulation VISSIM analysis added: Modeling of pedestrian activity based on LRT station boardings Additional truck traffic to reflect large existing truck stop Microsimulation approach

20 Simulation Differences in LOS/Delay seen only at the 51 st /I-10 WB intersection: Peak Hour Grade-Separated At-Grade Difference % AM Peak Hour C (25.3) D (35.9) % PM Peak Hour C (24.1) C (30.6) % However, they were due mostly to loss of off-ramp RTOR

21 The Diamond

22 Simulation

23 Recommendations At-grade LRT crossing of 51 st Ave may operate within acceptable limits of delay Recommend grade separation at 51 st Ave interchange: o 51 st Ave interchange was a worst case scenario compared to 59 th Ave, 67 th Ave and 75 th Ave interchanges

24 Recommendations No grade separations recommended at 59 th Ave, 67 th Ave and 75 th Ave interchanges: o 59 th Ave No freeway ramps, C-D road proposed as part of SR-202 system TI o 67 th Ave Lower traffic volumes compared to 51 st Ave o 75 th Ave No station proposed; lower existing traffic volumes

25 Bonus Material MTA Grade Crossing Policy Source: MTA Grade Crossing Policy, December 2003

26 Thank You! Authors: Nate Larson, PE, PTOE HDR, Seattle, WA Abhishek Dayal, AICP Valley Metro, Phoenix, AZ