Identification and Testing of Measures to Improve Work Zone Speed Limit Compliance

Thousands of crashes occur in work zones each year, leading to numerous fatalities and injuries. A sizeable portion of these crashes can be attributed to excessive speed, which emphasizes the need to motivate drivers to comply with speed limits in work zones. Motivating drivers to comply with traffic regulations is an extremely important yet challenging task in reducing the potential for conflicts and is critical to the safety of both motorists and workers. This research project was conducted to determine effective measures to motivate and encourage drivers to observe posted speed limits in work zones. Findings from literature and a survey of Department of Transportation (DOT) personnel indicate that a wide variety of methods have been tested to improve compliance. Methods for establishing work zone speed limits differ from state to state. Survey respondents widely regarded enforcement as the most effective treatment, but desired other effective methods to reduce costs and improve worker and officer safety. Three devices were tested in this project: speed display trailer, changeable message sign with radar, and orange-border speed limit sign. Results indicate that devices with the ability to display drivers' speeds have a noticeable effect on improving compliance. Orange borders greatly improve the visibility and conspicuity of speed limit signs, but they do not have a consistent measurable effect on compliance. In the absence of active enforcement, data from this project indicate that drivers are likely to drive as fast as they feel comfortable regardless of the posted speed limit.