Changes in crash risk following re-timing of traffic signal change intervals

More than I million motor vehicle crashes occur annually at signalized intersections in the USA. The principal method used to prevent crashes associated with routine changes in signal indications is employment of a traffic signal change interval--a brief yellow and all-red period that follows the green indication. No universal practice exists for selecting the duration of change intervals, and little is known about the influence of the duration of the change interval on crash risk. The purpose of this study was to estimate potential crash effects of modifying the duration of traffic signal change intervals to conform with values associated with a proposed recommended practice published by the Institute of Transportation Engineers. A sample of 122 intersections was identified and randomly assigned to experimental and control groups. Of 51 eligible experimental sites, 40 (78%) needed signal timing changes. For the 3-year period following implementation of signal timing changes, there was an 8% reduction in reportable crashes at experimental sites relative to those occurring at control sites (P = 0.08). For injury crashes, a 12% reduction at experimental sites relative to those occurring at control sites was found (P = 0.03). Pedestrian and bicycle crashes at experimental sites decreased 37% (P = 0.03) relative to controls. Given these results and the relatively low cost of re-timing traffic signals, modifying the duration of traffic signal change intervals to conform with values associated with the Institute of Transportation Engineers' proposed recommended practice should be strongly considered by transportation agencies to reduce the frequency of urban motor vehicle crashes.     

Characterizing red light runners following implementation of a photo enforcement program

Red light running causes about 260,000 crashes and 750 fatalities each year in the US (Retting, Ulmer, & Williams, 1999, Accident Analysis & Prevention). This study investigated the effects of photo enforcement cameras on reducing red light running and characterized the typical red light runner throughout photo enforcement program implementation. In Southeast Virginia, eight intersections were observed over an 8-month period during which photo enforcement cameras were installed at three sites. To assess spillover effects, three other sites served in a same city comparison group. Two additional sites from a nearby city served in a control group for city. Over 1750 light cycles were observed with red light running occurring at least once during 13% of these cycles. Predictors of red light runners included being at a site without a camera or at an intersection before deployment of cameras, being under the age of 26, being in the non-camera city, not using a safety belt, and driving in more traffic. While overall red light running decreased at camera sites, characteristics of the typical red light runner remained the same at camera and non-camera locations.     

Prevalence and characteristics of red light running crashes in the United States

About 40% of motor vehicle crashes occur at intersections. In recent years, the number of crashes at traffic signals has increased considerably. A major cause of such crashes is drivers disregarding traffic signals. Despite concerns about the frequent occurrence of red light violations and the significant crash consequences, relatively little is known about the overall prevalence and characteristics of red light running crashes. The present study examines the prevalence of red light running crashes on a national basis and identifies the characteristics of such crashes and the drivers involved. Cities with especially high rates of fatal red light running crashes are identified. Countermeasures to reduce red light running crashes based on collision patterns and characteristics of drivers involved are discussed. It was estimated that about 260 000 red light running crashes occur annually in the United States, of which approximately 750 result in fatalities. Comparisons were made between red light running drivers and drivers deemed not to have run red lights in these same crashes. As a group, red light runners were more likely than other drivers to be younger than age 30, male, have prior moving violations and convictions for driving while intoxicated, have invalid driver’s licenses, and have consumed alcohol prior to the crash. Comparisons also were made between characteristics of red light runners involved in daytime and nighttime crashes. Nighttime red light runners were more likely than daytime runners to be young, male, and have more deviant characteristics, 53% having high blood alcohol concentrations.     

Fatal red light crashes: the role of race and ethnicity

There is an increasing number of motor vehicle crashes (MVCs) in the U.S. that occur at intersections. Noncompliance with traffic signals is one of the causes for such increase. In this study, we focused on Hispanic drivers. It has been shown that failing to follow traffic laws and regulations is a major cause of MVCs in Latin America. Does this driving behavior in Latin America correspond to the Hispanic community in the U.S.? Are U.S. Hispanics more likely to die in a red light incident? Are Hispanics more likely to be red light runners than other racial/ethnic groups in the U.S.? We answered these questions by taking advantage of a 1990-1996 Fatality Analysis Reporting System (FARS) file with additional racial/ethnic information. Overall, we found no differences between African-American, White, and Hispanic drivers regarding red light running. We found that drinking and driving was the most important factor for red light running. However, we found evidence that some Hispanic subgroups may be more vulnerable to red light running. One such subgroup is formed by Hispanics who have no valid driver license and no record of previous driver license suspension. This study is the first to apply national, archival data to document the relevance of race/ethnicity to the red light running problem, and we hope that it might serve as an incentive for more research on this area.     

A nationwide survey of self-reported red light running: measuring prevalence, predictors, and perceived consequences

A United States probability sample of 880 licensed drivers participated in a telephone survey of red light running perceptions and behaviors. Despite most drivers believing red light running was problematic and dangerous, approximately one in five respondents reported running one or more red lights when entering the last ten signalized intersections. Among several demographic and attitude variables, only age group predicted recent red light running. Specifically, younger respondents were more likely to be violators. Drivers also reported being more likely to run red lights when alone, and were typically in a hurry when speeding up to be beat red lights. Contrary to expectations, frustration was not as important for predicting red light running as it was for other driving behaviors, such as speeding, tailgating, weaving, and gesturing angrily at others. Additionally, drivers perceived and received few consequences for running red lights. Less than 6% had received a traffic ticket for red light running and most believed that police would catch less than 20% of violators. Slightly more than one in ten had been involved in a red light running crash. Respondents most commonly suggested legal initiatives to reduce red light running. Accordingly, we recommend traffic safety experts pursue interventions that apply immediate and consistent negative consequences to violators to change the public's red light running perceptions and behavior.     

The effects of sunshields on red light running behavior of cyclists and electric bike riders

Bicycles held an important position in transportation of China and other developing countries. As accidents rate involving electronic and regular bicycles is increasing, the severity of the bicycle safety problem should be paid more attention to. The current research explored the effect of sunshields (a kind of affordable traffic facility built on stop line of non-motor vehicle lanes (According to National Standard in China, e-bikes share the non-motor vehicle lane with regular bikes.) which was undertaken to avoid riders suffering from sunlight and high temperature) on diminishing red light running behavior of cyclists and e-bike riders. An observational study of 2477 riders was conducted to record and analyze their crossing behaviors at two sites across the city of Hangzhou, China. Results from logistic regression and analysis of variance indicated a significant effect of sunshield on reducing red light infringement rate both on sunny and cloudy days, while this effect of sunshield was larger on sunny days than on cloudy days based on further analysis. The effect of intersection type in logistic regression showed that riders were 1.376 times more likely to run through a red light upon approaching the intersection without sunshields compared to with sunshields in general. The results of MANCOVA further confirmed that rates of running behaviors against red lights were significantly lower at the intersections with a sunshield than at intersections without sunshields when other factors including traffic flow were statistically controlled. To sum up, it is concluded that sunshields installed at intersections can reduce the likelihood of red light infringement of cyclists and e-bike riders on both sunny and cloudy days. For those areas or countries with a torrid climate, sunshield might be a recommended facility which offers an affordable way to improve the safety of cyclists and e-bike riders at intersections. Limitations of the current sunshield design and current study are also discussed.