National Academies Press: OpenBook
« Previous: Front Matter
Page 1
Suggested Citation:"1 Introduction." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
×
Page 1
Page 2
Suggested Citation:"1 Introduction." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
×
Page 2
Page 3
Suggested Citation:"1 Introduction." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
×
Page 3
Page 4
Suggested Citation:"1 Introduction." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
×
Page 4

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

NCHRP 3-78b: Final Project Report April 2016 1 1 INTRODUCTION This document is the draft final report of NCHRP Project 03-78B: Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. The primary deliverable of the project is a guidebook to provide guidance to engineers and planners on the design of roundabouts and channelized turn lanes ( C T L s ) for accessibility. The guidebook is available as a standalone publication. The accessibility of modern roundabouts and intersections with channelized (right) turn lanes is an important civil rights challenge in the United States that has broad potential implications for engineering practice in this country. The recently completed NCHRP Project 3-78A contributed significant conceptual, empirical, and analytical content to this accessibility discussion and resulted in published NCHRP Report 674: Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities (Schroeder et al., 2011a). This project builds on the results and lessons learned in NCHRP 03- 78A, and is tasked with developing a guidebook to serve as a hands-on resource for practitioners. NCHRP Project 03-78A was tasked with identifying and testing crossing solutions to assist pedestrians with vision impairments in crossing at modern roundabouts and at intersections with channelized turn lanes. The key products of that project included: (I) a framework for empirical study and analysis of accessibility performance, (II) identification and field testing of several treatments, and (III) research extension through modeling and simulation to expand the results beyond the field-tested sites. This research has the unique opportunity to advance the knowledge developed through NCHRP 3-78A by delivering (a) additional and streamlined field work targeting key knowledge gaps, (b) new prediction models tailored to crossing performance by pedestrians who are blind, (c) validation of previously- developed models with independent data, and (d) the development of engineering guidelines for the application of accessibility treatments. Since the publication of NCHRP Report 674, a significant amount of additional accessibility research has been conducted nationally. New research results available to support the guidelines development of this project include: - Before-and-after evaluation of two multi-lane roundabouts in Oakland County, Michigan equipped with Pedestrian Hybrid and Rectangular Rapid-Flashing Beacons (RCOC, 2011); - A Federal Highway Administration Project evaluating the accessibility performance of Rectangular Rapid-Flashing Beacons at multi-lane roundabouts in the US (FHWA, 2011); - Research on driver yielding behavior at eight US and four international two-lane roundabouts, predicting yielding based on geometric and operational factors (NIH, 2010, NSF 2012;) - Research on pedestrian crossing behavior and its effect on yielding of right-turning vehicles at signalized intersections (NIH, 2010); - Research on the effect of crosswalk location and traffic volumes at single-lane roundabouts (Guth et al., 2012) and channelized right turn lanes (Schroeder et al., 2006); - Research on wayfinding challenges at roundabouts and midblock crossings with a focus on treatments to assist blind pedestrians to locate crosswalks (NIH, 2010); - Research on nonvisual cues for promoting initial alignment at crosswalks and for staying within the crosswalk while crossing (Scott et. al., 2011a; 2011b); and - Publication and adoption of the second edition of Roundabouts: An Informational Guide (Rodegerdts, 2010). This final report documents and summarizes the project activities during the research. The report presents a summary of critical project tasks.

NCHRP 3-78b: Final Project Report April 2016 2 1.1 Research Objectives There were three major research objectives to NCHRP Project 3-78b: 1. The development of guidelines for the application of crossing solutions and treatment installations that will establish accessibility for pedestrians who are blind and who have low vision at modern roundabouts and channelized turn lanes, 2. The conduct of field-based research to gather accessibility data and test treatments at a broad sample of sites across the country, and 3. The extension of empirical field results through modeling to extrapolate crossing performance and impacts of vehicular traffic beyond the observed range of data. Guideline development is the first and foremost objective, with the second and third objectives being prerequisites and conduits for achieving the primary objective. The focus of the guidelines is on solutions that can be incorporated in the design phase and that can be installed and fully activated when the site opens to traffic. While engineers are faced with retrofit applications of these treatments, guidance is needed in the design stage to ensure accessibility of a new site in compliance with ADA from opening day. The guidelines consider the trade-offs between the needs of various users of a facility: pedestrians, including pedestrians with vision impairments or other disabilities, bicyclists, and vehicular traffic, including heavy vehicles such as trucks and buses. The developed guidance is intended to be directly usable as a decision-support tool by practicing engineers, while being a useful resource for other stakeholders in accessibility questions. In order to develop the guidelines for applications of treatments, the second objective is a well-targeted field research plan covering a breadth of sites and targeted to fill critical knowledge gaps in guideline development with empirical data. The research applied a newly developed Accessibility Audit study protocol, which streamlines collection of the key accessibility data from, and is applicable to a broad range of sites. The field data collection covered channelized turn lanes, single-lane, and two-lane roundabouts with various existing treatment combinations, including geometric configurations that may reduce speeds, encourage yielding, and thereby support the likelihood of an accessible crossing environment. The third objective is the enhancement of predictive models that supplement the empirical data collected, and extrapolate field results beyond the observed ranges. In NCHRP Report 674, the research team developed models to predict the delay experienced by a blind pedestrian at the three subject facility types as a function of driver yielding, pedestrian gap acceptance, and the utilization of these crossing opportunities. In parallel research, the team developed models to predict driver yielding and gap acceptance. This research proposed to mirror the delay modeling effort into safety prediction equations, as well as validate other models with new data. 1.2 Target Audience The guidebook and final report are targeted to an audience of practicing professional engineers, who in some cases may have little to no background in design for accessibility. The guidelines are therefore written in a way that is consistent with other engineering guidebooks (e.g. Roundabouts: An Informational Guide, ITE Traffic Engineering Manual, ITE Manual for Transportation Studies) to ensure its usability. At the same time, the guidelines are written to comply with American with Disabilities Act requirements for accessibility of written or electronic documents (Section 508 compliance), and are consistent with existing guidance on accessible design of pedestrian facilities and public rights of way. Given the sensitive political nature of this research, it is expected that the audience for these products extends well beyond the engineer tasked with designing a particular site. The group of stakeholders and those interested in this research most certainly includes planners and decision-makers at the municipal and state government levels, as well as FHWA, which is highly interested in establishing accessibility at all sites. The proposed team has a strong record of working collaboratively and effectively with these

NCHRP 3-78b: Final Project Report April 2016 3 stakeholders by relying on data-driven and non-confrontational working relationships. The audience further includes the US Access Board, which is tasked with writing technical specifications for implementing the American with Disabilities Act, and which has published proposed guidelines in the form of the Notice of Proposed Rulemaking for Accessible Pedestrian Facilities in the Public Right-of-Way. The team hopes that the results of this research will be useful to the Access Board by providing additional empirical evidence for or against the accessibility of a particular treatment. While the results of this research may not be available in time for the Final Rule, the team hopes that the results from this project will be instrumental in the discussion of equivalent facilitation requirements. Finally, this project has a broad public interest component, including professionals and researchers in the field of orientation and mobility, as well as private citizens with and without vision impairments. As such, the team is tasked with completing a product that is clear, concise, and technically sound to be useful as engineering guidelines, while also providing the broader context of this research to a much broader audience (presumably in the final project report). 1.3 Organization of Final Report This chapter provided a general introduction and background for the research. Chapter 2 presents a literature review, including specific discussion on research on crossing, wayfinding, and crossing treatments. Chapter 3 summarizes the study methodology, including field study protocols, site selection, and an overview of modeling efforts. Chapter 4 presents the field study results, including a summary of collected data, and a narrative of observations at the various sites visited. Chapter 5 summarizes the predictive models developed in this research, and Chapter 6 offers conclusions and recommendations. The main chapters are supported by five appendices. Appendix A presents details on the development of models to predict driver yielding, while Appendix B presents details on the risk model development. Appendix C discusses the approach for crossing sight distance evaluation. Appendix D presents details of the field study results and collected data. Finally, Appendix E presents photo logs of all sites studied as part of this research.

NCHRP 3-78b: Final Project Report April 2016 4 --- This page intentionally left blank ---

Next: 2 Literature Review »
Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 222: Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities provides guidance to engineers and planners on the design of roundabouts and channelized turn lanes for accessibility. NCHRP Web-Only Document 222 is the final report for NCHRP Research Report 834: Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities: A Guidebook.

The accessibility of modern roundabouts and intersections with channelized turn lanes is an important civil rights challenge in the United States that has broad potential implications for engineering practice in this country. This report builds on the results of NCHRP Report 674: Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. It provides a framework for empirical study and analysis of accessibility performance, documents field testing of several treatments, and provides a research extension through modeling and simulation to expand the results beyond the field-tested sites.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!