Countdown signals for motorized vehicles,which are intended to ensure safety on the road and regulate motor vehicle speed limits at road intersections,are still considered a relatively novel concept.These signals have...Countdown signals for motorized vehicles,which are intended to ensure safety on the road and regulate motor vehicle speed limits at road intersections,are still considered a relatively novel concept.These signals have been adopted by only a few countries,and the number of cities that use them is limited.This review aims to summarize the effects of countdown signals on traffic safety and efficiency and to determine the consistency and differences of existing research propositions on the matter.Based on the review,considerable research presents evidently different conclusions in the areas of driver red-light running and traffic safety.Particularly,some studies propose that countdown signals reinforce traffic safety,whereas others consider that such signals adversely affect traffic safety.Meanwhile,related literature provides varying conclusions on the aspect of traffic efficiency for vehicle headway.At present,the number of studies conducted regarding the driving behaviors of motorists toward countdown-signalized intersections is insufficient.Accordingly,such inadequate diversity in research causes difficulty in completely assessing the benefits and disadvantages of countdown signals.In this paper,an important future research direction on microcosmic driving psychological and physiological data combined with macro-driving behavior is proposed.展开更多
In many countries, traffic volumes and the number of drivers are rising faster than the availability of police officers whose routine duties include traffic law enforcement. Automated traffic enforcement, which produc...In many countries, traffic volumes and the number of drivers are rising faster than the availability of police officers whose routine duties include traffic law enforcement. Automated traffic enforcement, which produces photographic evidence of vehicles detected speeding or running red lights, can be used to supplement traditional enforcement. In the United States and Canada, a number of individuals and organizations have been very vocal in their opposition to automated traffic enforcement. They argue that automated enforcement programs are unnecessary for improving road safety, that they unfairly target relatively good drivers, and that they are motivated by revenue generation rather than safety. These arguments, however, often ignore the numerous peer-reviewed studies that have found real-world benefits in communities that use automated enforcement---cameras deter would-be violators, reduce crashes, and save lives. Solid, published research by a number of experts demonstrates that red light cameras save lives, and speed cameras substantially reduce speeding and speed-related crashes. Surveys of drivers and other road users indicate widespread support for automated enforcement. With regard to fairness, the objective of photo enforcement is to deter violations, not to surreptitiously catch violators. The more public the enforcement is, the better. If anything, automated enforcement programs improve fairness by reducing the potential for prejudicial enforcement. Finally, photo enforcement is intended to improve traffic safety by modifying the driver behaviors that lead to crashes, and it is reasonable to expect that people who break the law should pay for enforcing it. Ticket revenue should decline overtime as the cameras succeed in deterring would-be speeders and red light runners. This paper provides research-based responses to the critics＇ arguments as well as best practice guidelines for effective automated enforcement programs.展开更多
Red light running at signalized intersections is a major safety concern in the United States. Statistics show that approximately 45 percent of crashes at intersections caused by red light running re- sult in severe in...Red light running at signalized intersections is a major safety concern in the United States. Statistics show that approximately 45 percent of crashes at intersections caused by red light running re- sult in severe injuries and fatalities, while only approximately 30 percent of all other types of intersec- tion crashes cause injuries or fatalities. Over the past decade, many US cities and counties have de- ployed red light running photo enforcement systems for signalized intersections within their jurisdictions to potentially reduce red light running related crashes. This study proposes an empirical Bayesian （ EB ） before-after analysis method that computes a weighed sum of crashes observed in the field and crashes predicted by safety performance functions （SPFs） to mitigate regression-to-mean biases for analyzing crash reduction effects of red light running enforcement. The analysis explicitly considers red light run- ning related crash types, including head-on, rear-end, angle, tuming, sideswipe in the same direction, and sideswipe in the opposite direction; and crash severity levels classified as fatal, injury, and proper- ty damage only （PDO）. A computational study is conducted to examine the effectiveness of the Chica- go program with red light running photo enforcement systems deployed for nearly two hundred signal- ized intersections. It is revealed that the use of red light running photo enforcement on the whole is pos- itive, as demonstrated by reductions in all types of fatal crashes by 4-48 percent, and injury-related an- gle crashes by 1 percent. However, it slightly raises PDO-related angle crashes and moderately increa- ses injury and PDO related rear-end crashes. The safety effectiveness of red light running photo en- forcement is sensitive to intersection location.展开更多
基金support provided by the Shandong Provincial Natural Science Foundation of China(ZR2020MG021 and ZR2022MF332)the Humanities and Social Science Planning Fund of Chinese Ministry of Education(18YJAZH067).
文摘Countdown signals for motorized vehicles,which are intended to ensure safety on the road and regulate motor vehicle speed limits at road intersections,are still considered a relatively novel concept.These signals have been adopted by only a few countries,and the number of cities that use them is limited.This review aims to summarize the effects of countdown signals on traffic safety and efficiency and to determine the consistency and differences of existing research propositions on the matter.Based on the review,considerable research presents evidently different conclusions in the areas of driver red-light running and traffic safety.Particularly,some studies propose that countdown signals reinforce traffic safety,whereas others consider that such signals adversely affect traffic safety.Meanwhile,related literature provides varying conclusions on the aspect of traffic efficiency for vehicle headway.At present,the number of studies conducted regarding the driving behaviors of motorists toward countdown-signalized intersections is insufficient.Accordingly,such inadequate diversity in research causes difficulty in completely assessing the benefits and disadvantages of countdown signals.In this paper,an important future research direction on microcosmic driving psychological and physiological data combined with macro-driving behavior is proposed.
文摘In many countries, traffic volumes and the number of drivers are rising faster than the availability of police officers whose routine duties include traffic law enforcement. Automated traffic enforcement, which produces photographic evidence of vehicles detected speeding or running red lights, can be used to supplement traditional enforcement. In the United States and Canada, a number of individuals and organizations have been very vocal in their opposition to automated traffic enforcement. They argue that automated enforcement programs are unnecessary for improving road safety, that they unfairly target relatively good drivers, and that they are motivated by revenue generation rather than safety. These arguments, however, often ignore the numerous peer-reviewed studies that have found real-world benefits in communities that use automated enforcement---cameras deter would-be violators, reduce crashes, and save lives. Solid, published research by a number of experts demonstrates that red light cameras save lives, and speed cameras substantially reduce speeding and speed-related crashes. Surveys of drivers and other road users indicate widespread support for automated enforcement. With regard to fairness, the objective of photo enforcement is to deter violations, not to surreptitiously catch violators. The more public the enforcement is, the better. If anything, automated enforcement programs improve fairness by reducing the potential for prejudicial enforcement. Finally, photo enforcement is intended to improve traffic safety by modifying the driver behaviors that lead to crashes, and it is reasonable to expect that people who break the law should pay for enforcing it. Ticket revenue should decline overtime as the cameras succeed in deterring would-be speeders and red light runners. This paper provides research-based responses to the critics＇ arguments as well as best practice guidelines for effective automated enforcement programs.
基金partially supported by US Department of Transportation/Illinois Center for Transportation (No.D7752 2008-04435-04)
文摘Red light running at signalized intersections is a major safety concern in the United States. Statistics show that approximately 45 percent of crashes at intersections caused by red light running re- sult in severe injuries and fatalities, while only approximately 30 percent of all other types of intersec- tion crashes cause injuries or fatalities. Over the past decade, many US cities and counties have de- ployed red light running photo enforcement systems for signalized intersections within their jurisdictions to potentially reduce red light running related crashes. This study proposes an empirical Bayesian （ EB ） before-after analysis method that computes a weighed sum of crashes observed in the field and crashes predicted by safety performance functions （SPFs） to mitigate regression-to-mean biases for analyzing crash reduction effects of red light running enforcement. The analysis explicitly considers red light run- ning related crash types, including head-on, rear-end, angle, tuming, sideswipe in the same direction, and sideswipe in the opposite direction; and crash severity levels classified as fatal, injury, and proper- ty damage only （PDO）. A computational study is conducted to examine the effectiveness of the Chica- go program with red light running photo enforcement systems deployed for nearly two hundred signal- ized intersections. It is revealed that the use of red light running photo enforcement on the whole is pos- itive, as demonstrated by reductions in all types of fatal crashes by 4-48 percent, and injury-related an- gle crashes by 1 percent. However, it slightly raises PDO-related angle crashes and moderately increa- ses injury and PDO related rear-end crashes. The safety effectiveness of red light running photo en- forcement is sensitive to intersection location.
