A simple method for identifying and correcting crash problems on urban arterial streets.

Urban arterials by their nature carry heavy traffic volumes and generate large numbers of motor vehicle crashes. The present study involved review of police crash reports to identify precrash events and driver actions for a sample of crashes on urban arterials and describes a method for reducing such crashes based on analyses of collision patterns and identification of locations with excessive numbers of crashes of a particular type. Police-reported crash data were obtained for three urban arterials in the Washington, DC metropolitan area. A total of 2,013 crash reports were analyzed. Seven crash types accounted for nearly 90% of these reports. On each arterial studied, several locations with excessive numbers of crashes of a particular type were identified, and corresponding engineering countermeasures were recommended. Differences between the approach employed in this study and traditional blackspot analyses are discussed.

Fatal crash risk for older drivers at intersections.

Risk of fatal crash involvement was calculated for older drivers relative to drivers aged 40-49 in the United States during the years 1994-1995. The results indicated that drivers ages 65-69 were 2.26 times more at risk for multiple-vehicle involvements at intersections compared with 1.29 times more at risk in all other situations. The comparable figures for drivers aged 85 and older were 10.62 for multiple-vehicle involvements at intersections compared with 3.74 for all other situations. The relative crash risk was particularly high for older drivers at uncontrolled and stop sign-controlled locations; when traveling straight or when just starting to enter the intersection; and when the specific behavioral error in the crash was failure to yield. Countermeasures will likely involve reducing or simplifying the need to detect and evaluate moving traffic coming from the left and right when at intersections. This can be accomplished by traffic signals with protected left turns, four-way stop signs, and one-way streets. Whereas such devices involve significant cost in terms of dollars and travel delay, their cost-effectiveness may have to be revisited as the United States population continues to age.

Classifying urban crashes for countermeasure development.

Efforts to reduce urban crash rates have been hampered by a lack of information about motor vehicle crash types. The present study is based on a systematic sample of 4,526 police crash reports from four urban areas. The sample was weighted to give each area equal representation. Diagrams and narrative descriptions from each report were reviewed, and the most common crash types based on precrash driver/vehicle behavior, were identified. Fourteen crash types were defined, and five of these were found to account for 76% of all crash events and 83% of injury crashes. Although the rank order of the five types differed from city to city, they accounted for the vast majority (69%-81%) of the crashes in each. Potential countermeasures are discussed based on the predominant crash types identified in this study. For example, ran traffic control crashes, the most common types, might be reduced by changes in signal timing, providing all-red signal intervals, increasing sign visibility, and increasing sight distances.

Characteristics of fatal crashes of 16-year-old drivers: implications for licensure policies.

Compared with older drivers, and even older teens, greater percentages of 16-year-old drivers in fatal crashes were involved in single-vehicle crashes, were responsible for their crashes, were cited for speeding, had high vehicle occupancy (especially other teenagers), and were female. Sixteen-year-olds were less likely than older drivers to have been drinking. In addition, their crashes occurred at different times than those of older drivers, crashes between 10:00 p.m. and 11:59 p.m. on Fridays and Saturdays being especially likely. Information about the characteristics of the crashes of 16-year-olds is important because this is the age at which most states currently allow teenagers to get an unrestricted driver's license. It is also the age at which restrictions on beginning licenses are being considered in some states. The results of this study suggest that restrictions on teenage passengers, and night-driving curfews with pre-midnight starting times--two provisions used in New Zealand's graduated licensing system--would be appropriate in attempts to reduce crashes of beginning 16-year-old drivers, who have the highest fatal crash rate of any single teen age.