Use of Blue Lights on Paving Equipment in Work Zones

Vehicle speed in work zones is a significant concern to ODOT and construction partners. Prior national research shows that law enforcement vehicles located within a work zone with active flashing blue lights result in reduced vehicle speeds. Placement of flashing blue lights on construction equipment has been identified as a potential control measure to further reduce speeds. The goal of this research study is to conduct an initial evaluation of the impact of flashing blue lights located on construction equipment on the speed of passing vehicles in work zones. The research design consisted of a controlled experiment involving flashing blue lights mounted on the rear of the paver during mainline paving operations on three case study projects on high speed roadways in Oregon. Vehicle speed data was collected during multiple work shifts on each case study, both with and without the flashing blue lights on. The experimental results reveal that vehicle speed is affected by the presence of flashing blue lights. Speed differentials between the road work ahead sign and the first exposure to the paver resulted in greater speed reductions in all three case studies when the flashing blue lights were on. Additionally, within the active work area at distances upstream of the paver where the driver can see and react to the blue lights, mean vehicle speeds tended to be lower when the blue lights were on. Closer to, immediately adjacent, and downstream of the paver, the amount of reduction in mean speed was typically less or none at all with the blue lights on; in some cases the mean speeds were higher with the blue lights on. Generalization of the results to all projects with a high level of confidence is limited given the low number of case study projects and the presence of confounding variables.