Cover Image

Not for Sale



View/Hide Left Panel
Click for next page ( 89


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 88
88 readily crossed at the DAV-CLT single-lane roundabout while well beyond the scope of this report. All participants in this others experienced over 80 s of average delay. research were familiarized with the test location by walking Also coming into play was the situation behind the lead the perimeter of the site, by exploring the geometry through vehicle. If there was no vehicle following the lead vehicle so use of a tactile map, and by performing some (assisted) practice closely that there was a high chance of a collision, the O&M crossings prior to starting the actual experiment. specialist often did not intervene. Participants apparently were During orientation to the study, participants did not receive often unaware that a vehicle was approaching. Also, many any instruction in making crossing decisions. This lack of participants crossed when a vehicle had yielded for them but instruction from the O&M specialist was part of the research they did not realize that a vehicle had yielded until it accelerated protocol, and participants were told that instruction or feed- across the crosswalk after they had crossed. In short, while the back would not be provided. However, it may have resulted frequency of interventions was relatively low, conversations in some participants assuming that they were making good with participants after trials and after the study led the team decisions about crossings if interventions did not occur, when to believe that the participants often were unaware of the in fact the O&M specialist recognized that the situation was situation when they crossed the street. potentially risky but did not intervene because she knew that Some variability in performance may have been due to par- the approaching vehicle could (and was) taking evasive action ticipant behavior. The team presumes that some behaviors (usually braking or accelerating to pass the crosswalk before result in lower risk crossings than others, but the team did not the pedestrian arrived in the case of the two-lane roundabout). manipulate participant behavior and did not explicitly study Also, some participants stepped out at times that forced a it. Some participants stood very upright and still while listening yield, apparently without realizing they were doing so. In this and waiting to cross, with their canes held vertically in front situation the O&M specialist did not intervene if she was con- of their bodies, while others leaned forward as they anticipated fident that the vehicle was yielding and would stop in time, crossing or took a step forward and extended their canes. Some even in situations of relatively fast vehicle deceleration. turned their heads toward the traffic (and may have been per- In this research, the single-lane roundabout in Golden pro- ceived as looking at traffic) and others looked down while vides insights into the effect of added exposure or experience listening. These various postures appeared to the research on crossing. Since no treatments were installed at the site, the team to affect yielding behavior and crossing behavior. A lack pretestposttest comparison represents a control for any learn- of training on roundabout crossings also may have allowed ing effect that may have affected the concurrent Golden two- participants to use less than optimal techniques. lane roundabout study. Since no such effect was measured, two The same general points made above for roundabouts conclusions can be drawn. First, the pretestposttest improve- appear to be true for CTLs. Many of the blind participants did ments in crossing performance at the two-lane roundabout not understand the layout of the CTL before the familiariza- are likely attributable to a treatment effect and not a learning tion provided as part of the study. For example, they were effect. Second, the repeated exposure (twice) of participants to unaware of the potential crosswalk locations, the shape of the the same single-lane roundabout did not significantly improve island, and the addition of a deceleration lane at the intersec- their crossing performance. tion, and many were confused about the fact that the signal While anecdotal evidence suggests that participants were did not also control the right turn lane. Pedestrians who are more comfortable in the second round of exposure (the post- blind may also benefit from instruction that helps them better test), their earlier experience at the roundabout was not O&M understand the geometry and traffic flow at CTLs and various training or instruction, which might be beneficial, particularly crossing strategies. It is hypothesized that even with intense at single-lane roundabouts. and repeated O&M training, many of the crossing challenges It's possible that O&M instruction may have a more signifi- at busy and high-speed crossings cannot be alleviated. Accord- cant and permanent effect. There is clearly a need for education ingly, additional infrastructure-based treatments as tested of pedestrians who are blind or visually impaired about round- in this research are needed to satisfy concerns of pedestrian abouts, including how to make safe crossings. Just as little is accessibility. known about the most appropriate engineering treatments for promoting the accessibility of roundabouts, little is known about the most appropriate crossing strategies for blind pedes- Learning Effect and O&M Training trians. As illustrated by this project, the engineering profes- The inter-participant variability raises the question of sion and the O&M profession must work together to promote whether individual travel skills can be improved through train- accessibility. It is therefore essential that engineering profes- ing and education, to the point where they represent a viable sionals have a general understanding of the O&M profession, treatment to enhancing accessibility. This form of training is and vice versa. What follows are some general principles of the basis of the field of orientation and mobility, which goes O&M instruction to help promote this mutual understanding.