Speed Variation and Safety in Work Zones

In addition to lower speeds, the difference between vehicle speed and the average speed on the roadway has been identified as a factor in roadway crashes. For work zones, the potential for such speed variation from the average speed is magnified. The safety associated with speed variation in work zones affects both motorists driving through the work zone and the workers in the work zone. The overall goal of this research is to develop additional knowledge and practices that can be used to improve driver and worker safety in work zones and, as a result, mobility through work zones. The research focuses on high-speed roadways (e.g., highways and freeways) and typical mobile construction and maintenance operations that occur on such roadways (e.g., paving and restriping). The research presented in this report involved a review of the archival literature germane to the topic of speed variation (with and without a work zone), the analysis results of speed variation and crash occurrence, and the impacts of selected traffic control interventions on speed variation in work zones in Oregon. The PCMS unit showing alternating messages “MAINTAIN CONSTANT SPEED” and “THRU WORK ZONE” in two phases and placed at the advance warning area was found to effectively reduce speed variation in the work zone. Based on the findings, the researchers recommend use of PCMS units that display custom messages to maintain constant speed for work zone operations on high-speed roadways.