Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes to Assist Pedestrians with Vision Disabilities

Accessibility of modern roundabouts and channelized turn lanes to pedestrians with vision disabilities has been a focus of recent and ongoing research. Initial research results documenting the crossing challenges for pedestrians with vision disabilities at these facility types motivated the original National Cooperative Highway Research Program (NCHRP) Project 3-78A research effort and had an influence on language in the Proposed Accessibility Guidelines for Pedestrian Facilities in the Public Right-of-Way (draft PROWAG) published by the U.S. Access Board in 2011. That document provides technical specifications for making sidewalks and intersections in the public rights-of-way compliant with the American with Disabilities Act (ADA). Specifically, the provision of a pedestrian-actuated signal with an Accessible Pedestrian Signal (APS) fulfills accessibility requirements for multi-lane approaches at roundabouts and channelized turn lanes in the draft PROWAG. However, ADA regulations allow the use of alternative treatments, if those treatments provide facilities (crosswalks) that are "accessible to and usable by" individuals with disabilities (called equivalent facilitation in ADA regulations). The draft PROWAG does not specifically discuss crossing treatments for single-lane approaches on these facilities. With the impending publication of PROWAG and its expected adoption by the U.S. Department of Justice and U.S. Department of Transportation, municipalities and state DOTs need more specific guidance on what may constitute equivalent facilitation to pedestrians with vision disabilities at these facility types. NCHRP Project 3-78A was tasked with exploring crossing solutions for single-lane and multi-lane crossings. The research was based on the premise that other treatments exist besides an APS-equipped signal that can establish access to these facilities to pedestrians who are blind, while reducing installation cost and impact to vehicular traffic. In particular, the NCHRP Project 3-78A work (published in NCHRP Report 674: Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities) tested two treatments at a two-lane roundabout that showed promise in terms of reducing pedestrian delay and risk. The work accomplished during NCHRP Project 3-78A sets the stage for continuing research. First, the research developed a framework for quantifying pedestrian accessibility, thus enabling a direct comparison of the accessibility impacts of two or more conditions (for example, evaluation of pre-post treatment effect; comparison of two test sites; or contrast of different pedestrians at a site). Second, the NCHRP Project 3-78A research tested several crossing treatments that showed potential for improving pedestrian access to two-lane crossings (e.g., raised cross walk (RCW) and pedestrian hybrid beacon (PHB)), and others that left pedestrians with significant challenges when attempting to cross at single-lane channelized turn lane crosswalks. The research found that effectiveness of crossing treatments varied depending on the site characteristics, and that more research at additional sites is needed to strengthen the results. Third, the research developed ways to extend the research to other sites, geometries, and traffic volume patterns through mathematical delay models and through modeling in a micro-simulation environment. Combined, these three aspects provide a sound experimental and practical base for follow-up research that help address issues and questions that confront municipalities and state departments of transportation (DOTs): Which (if any) are the most cost-effective, site-specific treatments that successfully establish equivalent facilitation to pedestrians with vision disabilities under prevailing geometric and operational conditions, while balancing the impact to the traveling public? The completed NCHRP Project 3-78A effort devoted a large portion of time to developing a short list of treatments, to identifying treatment locations, and to defining an analysis framework and performance measures for pedestrian accessibility. With those pieces in place, and with the initiative taken by agencies across the country, there is significant momentum for continued research leading towards decision support for state and local governments in this area. The objective of this research is to develop guidelines for the installation of pedestrian crossing solutions at roundabouts and channelized turn lanes that address accessibility for pedestrians with vision disabilities. Specifically, guidelines need to consider multiple alternatives for a range of geometric and traffic operational conditions. The guidance needs to focus on solutions that can be incorporated in designs now and can be installed and fully activated when the roundabout is opened to the public. The research will efficiently extend field work by capitalizing on the findings from NCHRP Project 3-78A and on initiatives taken by agencies across the country in installing solutions. The field work will cover selected channelized turn lanes, single-lane roundabouts, and two-lane roundabouts at a greater sample size than NCHRP Project 3-78A, that will be made possible by a condensed and well-targeted data collection protocol that reduces the number of participants per site, while maintaining statistical power. Further, each proposed case will include multiple (up to three) crosswalks in close proximity for added sample size. The research will further be supported by extension of the research results to other geometries and traffic patterns through mathematical modeling and simulation. The goal of this effort is to define as accurately as possible the operational conditions under which certain solutions are thought to establish accessibility. The final report will provide engineers and others with more specific guidance for when (and if) a particular solution is recommended.


  • English


  • Status: Active
  • Contract Numbers:

    Project 03-78B

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway & Transportation Officials

    444 North Capitol Street, NW, Suite 225
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Parker, Stephan

  • Performing Organizations:

    North Carolina State University

    Institute for Transportation Research and Education
    Campus Box 8601
    Raleigh, NC  United States  27695-8601
  • Principal Investigators:

    Schroeder, Bastian

  • Start Date: 20130612
  • Expected Completion Date: 0
  • Actual Completion Date: 20150611
  • Source Data: RiP Project 37836

Subject/Index Terms

Filing Info

  • Accession Number: 01543910
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 03-78B
  • Files: TRB, RiP
  • Created Date: Nov 23 2014 1:00AM