Simulating the Impact of Traffic Calming Strategies

This study assessed the impact of traffic calming measures to the speed, travel times and capacity of residential roadways. The study focused on two types of speed tables, speed humps and a raised crosswalk. A moving test vehicle equipped with GPS receivers that allowed calculation of speeds and determination of speed profiles at 1s intervals were used. Multi-regime model was used to provide the best fit using steady state equations; hence the corresponding speed-flow relationships were established for different calming scenarios. It was found that capacities of residential roadway segments due to presence of calming features ranged from 640 to 730 vph. However, the capacity varied with the spacing of the calming features in which spacing speed tables at 1050 ft apart caused a 23% reduction in capacity while 350-ft spacing reduced capacity by 32%. Analysis showed a linear decrease of capacity of approximately 20 vphpl, 37 vphpl and 34 vphpl when 17 ft wide speed tables were spaced at 350 ft, 700 ft, and 1050 ft apart respectively. For speed hump calming features, spacing humps at 350 ft reduced capacity by about 33% while a 700 ft spacing reduced capacity by 30%. The study concludes that speed tables are slightly better than speed humps in terms of preserving the roadway capacity. Also, traffic calming measures significantly reduce the speeds of vehicles, and it is best to keep spacing of 630 ft or less to achieve desirable crossing speeds of less or equal to 15 mph especially in a street with schools nearby. A microscopic simulation model was developed to replicate the driving behavior of traffic on urban road diets roads to analyze the influence of bus stops on traffic flow and safety. The impacts of safety were assessed using surrogate measures of safety (SSAM). The study found that presence of a bus stops for 10, 20 and 30 s dwell times have almost 9.5%, 12%, and 20% effect on traffic speed reductions when 300 veh/hr flow is considered. A comparison of reduction in speed of traffic on an 11ft wide road lane of a road diet due to curbside stops and bus bays for a mean of 30s with a standard deviation of 5s dwell time case was conducted. Results showed that a bus stop bay with the stated bus dwell time causes an approximate 8% speed reduction to traffic at a flow level of about 1400 vph. Analysis of the trajectories from bust stop locations showed that at 0, 25, 50, 75, 100, 125, 150, and 175 feet from the intersection the number of conflicts is affected by the presence and location of a curbside stop on a segment with a road diet.

Language

  • English

Project

  • Status: Completed
  • Funding: $96307
  • Contract Numbers:

    DTRT13-G-UTC60 TRC-17-10

  • Sponsor Organizations:

    Office of the Assistant Secretary for Research and Technology

    University Transportation Centers Program
    Department of Transportation
    Washington, DC  United States  20590
  • Managing Organizations:

    Transportation Research Center for Livable Communities

    Western Michigan University
    Kalamazoo, MI  United States  49009-5316

    Western Michigan University

    1903 W. Michigan Avenue
    Kalamazoo, MI  United States  49008-5241
  • Project Managers:

    Dunn, Denise

  • Performing Organizations:

    Tennessee State University

    Nashville, TN  United States  37209

    Transportation Research Center for Livable Communities

    Western Michigan University
    Kalamazoo, MI  United States  49009-5316
  • Principal Investigators:

    Chimba, Deo

    Triplett, Kimberly

  • Start Date: 20170815
  • Expected Completion Date: 20190630
  • Actual Completion Date: 20190630
  • USDOT Program: University Transportation Centers
  • Subprogram: Research
  • Source Data: https://wmich.edu/sites/default/files/attachments/u883/2019/TRCLC_RR_17-10.pdf

Subject/Index Terms

Filing Info

  • Accession Number: 01646391
  • Record Type: Research project
  • Source Agency: Transportation Research Center for Livable Communities
  • Contract Numbers: DTRT13-G-UTC60 TRC-17-10
  • Files: UTC, RiP
  • Created Date: Sep 22 2017 1:02PM