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86 the third exhibited high delays. There was high inter-participant yield or crossable gap in both lanes. However, the analysis variability that emphasizes differences among individual blind showed that the rate of occurrence of these types of opportuni- travelers. ties can be low, resulting in high pedestrian delays. The occur- Another important finding was the difficulty and level of rence of dual crossing opportunities is expected to be even risk encountered by blind pedestrians when attempting to less at approaches with higher conflicting volumes and speeds. cross a relatively high-speed, high-volume CTL. A sound- In addition to delay, participants experienced a significant strip treatment did not prove to be effective in reducing risk, amount of risk, as indicated by the frequency of O&M inter- partly due to the high noise levels and difficulty of auditory ventions. Both delay and risk were reduced with the installation detection in noise, and partly due to the lower sound output of each of the two tested treatments (PHB and RCW), thereby of the sound strips when vehicles were moving slowly over improving the accessibility and usability of the site. Before treat- them. A pedestrian-actuated beacon with an audible message ment installation, the same participants experienced higher improved yielding behavior somewhat, but the posttest cross- delay and greater risk at the two-lane crossings compared to ing performance was still associated with a high rate of O&M the single-lane roundabout. After treatment installation, the interventions. Consequently, the accessibility of this CTL site crossing performance at the two-lane approaches improved was not established with the treatments tested. Attention to levels comparable to the tested single-lane roundabout needs to be given to this access issue in addition to the atten- crossings without treatments. However, some safety concerns tion to accessibility of roundabout crossings. remained at the RCW, evident by other risky events (that In general, these studies have shown that the tested treat- did not result in interventions) that were noted by a trained ments can, in fact, change the behavior of drivers as well as observer recording data during the studies. pedestrians and that these changes can be measured and quan- While some of the tested single-lane approaches seemed tified. The treatments differed in their effect on drivers and more easily crossable than an untreated two-lane approach, on pedestrians who are blind, and represent various degrees some exceptions need to be highlighted. In particular, the high- of installation cost and impact to the driver and pedestrian speed, high-volume, single-lane CTL crossings resulted in very high delays and the highest risk for any of the test sites. Also, populations. The results and conclusions previously discussed the Raleigh roundabout had high intervention rates despite should not be construed as absolute, and readers should lower speeds and generally courteous driver behavior. Con- remain cautious about basing policy decisions on these limited sequently, even a single-lane crossing can be challenging and data. This report provides a firm conceptual measurement- potentially dangerous to cross if traffic volumes, vehicle speeds, driven approach to the study of the effect of such treatments, and driver behavior are not conducive to crossings by pedes- but it is clear that more field research is needed to explore and trians who are blind. substantiate treatment effects. The Impact of Vehicle Speed Discussion High vehicle speeds have been linked to a decreased likeli- In the following, the team offers some additional discus- hood of driver yielding (Geruschat and Hassan 2005) and are sion to highlight various aspects of the field study results. The further associated with an increased pedestrian injury rate section will highlight specific aspects of the study results that when collisions occur. In the context of pedestrian crossings are important in guiding the decision-maker in evaluating the at roundabouts and CTLs, a "high speed" is categorized as a level of accessibility of a given crosswalk to pedestrians who design speed or average observed speed at the crosswalk greater are blind and who are relatively experienced travelers. than 20 mph. In this research, the high-speed channelized right turn Single-Lane Versus Two-Lane Approaches lanes resulted in the greatest pedestrian delay and risk, sup- porting the hypothesis that pedestrian accessibility is tied to A pedestrian crossing with two conflicting lanes is gener- vehicle speeds. The treatment effect of the RCW at the two-lane ally more challenging than one with a single lane because roundabout provides further evidence for this. The RCW sig- the vehicle state in both lanes affects the decision-making. nificantly reduced pedestrian delay and reduced risk while Visual obstruction and auditory masking of vehicles in the not being associated with any form of red signal display like near lane may block activity in the far lane, which may result the pedestrian hybrid beacon. After RCW treatment installa- in multiple-threat situations (Zegeer et al. 2002). tion, only a small percentage of drivers passed in front of the The experiments at the Golden two-lane roundabout showed waiting pedestrian without yielding at the tested location. The that pedestrians who are blind are often capable of utilizing findings on vehicle speed have two primary implications for dual crossing opportunities at this location, characterized by a practitioners: