Pedestrian Access to Roundabouts: Assessment of Motorists' Yielding to Visually Impaired Pedestrians and Potential Treatments to Improve Access
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The FHWA'S Intersection Safety Research Program is focused on improving highway safety through increasing knowledge and understanding of the effects of intersection design on safety and operational efficiency. Roundabout intersections have been shown to have both safety and operational benefits compared to alternative stop-controlled and signalized intersections; however, these benefits do not necessarily extend to all users. In particular, pedestrians who have visual impairments have reported difficulty using the pedestrian facilities at some roundabouts. The present studies were intended to document some of the difficulties pedestrians with visual impairments face and test potential treatments to improve roundabout accessibility for all users.
Michael F. Trentacoste
Director, Office of Safety
Research and Development
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TECHNICAL REPORT DOCUMENTATION PAGE
|1. Report No.
|2. Government Accession No.
||3. Recipient's Catalog No.
|4. Title and Subtitle
Pedestrian Access to Roundabouts: Assessment of Motorists' Yielding to Visually Impaired Pedestrians and Potential Treatments To Improve Access
|5. Report Date
|6. Performing Organization Code
Vaughan W. Inman, Gregory W. Davis, and Dona Sauerburger
|8. Performing Organization Report No.
|9. Performing Organization Name and Address
1710 SAIC Dr
McLean, VA 22102
|10. Work Unit No. (TRAIS)
|11. Contract or Grant No.
|12. Sponsoring Agency Name and Address
Office of Safety Research and Development
Federal Highway Administration
6300 Georgetown Pike
McLean, VA 22101-2296
|13. Type of Report and Period Covered
Final Report: October 2003-Jan 2005
|14. Sponsoring Agency Code
|15. Supplementary Notes
Prepared for: Joseph G. Bared, Ph.D., Office of Safety Research and Development, HRDS-05.
This report describes two related studies intended to address double-lane roundabout accessibility issues for visually impaired pedestrians. The first study
was conducted on a closed course to evaluate the feasibility of a pavement treatment to alert blind pedestrians when vehicles have yielded to them. The
second study examined drivers' yielding behavior at a two-lane roundabout and the effectiveness of the same roadway treatment in an operational environment.
In the first study, there were two experimental conditions: a control condition and a treatment condition in which rumble strip-like devices were placed on
the roadway surface. Seven individuals who have severe visual impairments participated. Participants stood at a crosswalk and used hand signals to indicate
when they detected vehicles stopping or departing after a stop. Compared to the control condition, the sound strips treatment increased the probability of
detecting stopped vehicles, and decreased by more than a second the amount of time needed to make a detection; however, the treatment did not reduce the number
of false detections. False detections could result in the pedestrian crossing when moving vehicles are approaching the crosswalk.
The second study was an experiment conducted at an operating roundabout. In that environment the rumble strip-like treatment was not effective, probably
because the majority of vehicles stopped in the circular roadway before crossing over the rumble strips. A Yield to Pedestrians, State Law sign that was placed
in the roundabout exit between the two travel lanes resulted in an increase in drivers' yielding from 11 percent of vehicles in the control condition to 16
percent in the experimental condition.
It was concluded that the treatments explored in these studies do not appear promising for double-lane roundabouts, but should be explored further to see
if they might work at single-lane crossings.
|17. Key Words
Visual Impairment, Pedestrian, Roundabout, Accessibility, Yielding, Crosswalk
|18. Distribution Statement
No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161.
|19 Security Classification (of this report)
|20. Security Classification (of this page)
|21. No. of Pages
|Form DOT F 1700.7
||Reproduction of completed page authorized.
SI* (Modern Metric) Conversion Factors
TABLE OF CONTENTS
LIST OF FIGURES
Figure 1. Illustration of single-lane roundabout with crosswalks.
Figure 2. MUTCD R1–6.
Figure 3. MUTCD R1–5.
Figure 4. Layout of closed-course test facility.
Figure 5. Example of driver's script.
Figure 6. Proportions of correct identifications of stopped vehicles shown by test condition,
the lane in which the first vehicle to yield stopped, and the lane identified.
Figure 7. Roundabout exit in baseline configuration.
Figure 8. Sound-strip installation and mount for the street sign.
Figure 9. Distance from crosswalk of vehicles stopping in the near lane.
Figure 10. Two vehicles that stopped for the pedestrians.
Figure 11. Distance between the crosswalk and a vehicle stopped in the far lane is shown as a function of treatment condition.
Figure 12. Pedestrians crossing after a correct detection of both lanes blocked.
Figure 13. Frequencies of delays between the time both lanes were blocked and when participants indicated both lanes were blocked.
Figure 14. Amount of time drivers waited before moving on.
LIST OF TABLES
Table 1. Percentage of detection accuracy for vehicles blocking each lane.
Table 2. Correct detection of pairs of vehicles yielding side-by-side at the same time.
Table 3. Drivers’ responses to the presence of visually impaired pedestrians in the crosswalk.
Table 4. Lateral position of vehicles that stopped for pedestrians.
Table 5. Trial outcomes.
Table 6. Average wait time before the first double yield.