Safety Impacts and Other Implications of Raised Speed Limits on High-Speed Roads. Final Report

摘要

This report describes the analyses performed and results obtained by a study of safety and other impacts of speed limit changes on high-speed roads. Safety-related analyses were based on a comprehensive framework of the disaggregate relationships between speed limits, driver speed choices, crash occurrence and crash severity. Using a variety of datasets, the project conducted numerous statistical analyses to elucidate and quantify these relationships. The project identified a relatively small but statistically significant correspondence between speed limits and total crash rates: a speed limit increase from 55 to 65 mi/h on an average high-speed road section would be associated with a crash rate increase of around 3%. Finally, the project found a statistically significant association between speed limits and the distribution of injury severities following a crash.