This study was conducted to identify the potential of fluorescent orange sheeting, an innovative message sign, and a changeable message sign with radar (CMR) for reducing speeds in highway work zones. It investigates the effect of each strategy right after implementation as well as several weeks after implementation. In addition to the overall effect of each strategy on all vehicles, the study includes the effect on specific vehicle types during varying lighting conditions. The researchers collected traffic data before, immediately after, and 2-3 weeks after implementation of each strategy (three consecutive weeks for the CMR). They collected data upstream of the work zone, in the advance warning area, and adjacent to the active work area. They used various statistical tests to evaluate the significance of speed changes from phase to phase and adjusted vehicle speeds with the upstream speed changes over time. Results indicate that fluorescent orange sheeting and the innovative message sign do help reduce speeds at highway work zones. There is, however, a novelty effect, and speeds tend to return to normal after a certain period of time. Moreover, both strategies influence reduced vehicle speeds more during the day than at night. Passenger vehicles tend to decrease their speeds more than trucks. CMR radar significantly reduces vehicle speeds in the immediate vicinity of the sign and are not sensitive to a novelty effect.
Abstract