Pedestrian countdown signals installed at five intersections in Montgomery County, Maryland, were evaluated with a before-and-after study. The effect of the countdown signals on pedestrian and motorist behavior was determined by observing the signal indication when pedestrians entered the intersection, the number of pedestrians remaining in the intersection at the release of conflicting traffic, conflicts between pedestrians and motor vehicles, and vehicle approach speeds to the intersections. On the basis of the observational study, the pedestrian countdown signals did not have a negative effect on pedestrian behavior. The vehicle speed observations found that pedestrian countdown signals had no effect on vehicle approach speeds during the pedestrian clearance interval (i.e., flashing "Don't Walk" indication). Pedestrian behavior observations found that although 2 of the 20 crosswalks experienced a statistically significant decrease in the number of pedestrians who entered on "Walk," 6 crosswalks experienced a significant increase. Additionally, none of the intersections had a significant increase in the number of phases with pedestrians remaining in the intersection at the release of conflicting traffic. The observational study of conflicts found a significant decrease in pedestrian-motor vehicle conflicts after the installation of the pedestrian countdown signals at four of the intersections at which conflicts were observed. A survey of pedestrians was also conducted. Results of the survey indicated that, generally, pedestrians are aware of the countdown signal and understand the countdown indication.
The use of red light camera (RLC) systems has risen dramatically in the United States in recent years. The size of the problem, the promise shown by RLC systems in other countries, and the paucity of definitive U.S. studies have motivated a multijurisdictional U.S. study. The fundamental objective of this study, which was sponsored by FHWA, was to determine the effectiveness of the RLC systems in reducing crashes at monitored intersections as well as jurisdictionwide. Phase I involved the development of a detailed experimental design that included collection of background information, establishment of study goals, selection of potential study jurisdictions, and specification of statistical methodology. In Phase 2, an empirical Bayes before-and-after study used data from seven jurisdictions across the United States, with a total of 132 treatment sites. Effects detected were consistent in direction with those found in many previous studies—a decrease in right-angle crashes and an increase in rear-end crashes—although both effects are somewhat lower than those reported in many sources. The extent to which the increase in rear-end crashes negates the benefits for right-angle crashes is unclear and points to the need for an examination of the economic cost of crashes, which is the subject of a companion paper, to aggregate the effects on rear-end, right-angle, and other crash costs. That second paper seeks to isolate all factors that would favor the installation of RLC systems by using the aggregate economic benefit as the outcome variable. There were weak indications of a spillover effect, which point to a need for a more definitive, perhaps prospective, study of this issue.
There is a need to evaluate low-cost safety strategies that states may implement as part of their Strategic Highway Safety Plan. FHWA organized a pooled fund study of 26 states to evaluate several low-cost safety strategies, including the reallocation of total paved width. This study identifies whether it is safer to increase lane width or increase shoulder width given a fixed total width. Geometric, traffic, and crash data were obtained for more than 52,000 mi of roadway in Pennsylvania and Washington State. A case-control approach was applied to evaluate the safety effectiveness of various lane–shoulder configurations. There was a general reduction in the odds ratio as total paved width, lane width, and shoulder width increased individually; this is consistent with previous research. However, the primary research objective was to estimate the safety effectiveness of reallocating a fixed total paved width. Individual state results did not indicate a clear trade-off between lane and shoulder width for a fixed total width. Supplementing the results of this study with previous research, crash modification factors (CMFs) are provided for several lane–shoulder combinations. The selected values present a more apparent trade-off, indicating a slight benefit to increasing lane width for a fixed total width. Importantly, the results differ from other studies that developed CMFs without considering the interaction between lane and shoulder width, including those studies currently referenced in the Highway Safety Manual. This raises the question of whether CMFs should reflect the interaction between lane and shoulder width.
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