Implementing Speed Reductions at Specific Interstate Workzones from 65 MPH to 35 MPH

Interstate preservation projects are commonly conducted at night and often require working in close proximity to ongoing traffic. Vehicle speed and speed variability in work zones is inextricably connected to the work zone design and the selected traffic control devices. To provide guidance on how to effectively and efficiently reduce traffic speeds, the Oregon Department of Transportation conducted a research study to investigate the impact of selected traffic control devices on vehicle speed within highway paving project work zones. The research centered around two case studies on multi-lane paving projects in Oregon. On each case study, the researchers implemented multiple traffic control devices (portable changeable message signs (PCMS), radar speed display, police officer presence, tubular markers and drums on both sides of travel lane) and evaluated their impact on vehicle speed, construction productivity, cost, and motorist and worker safety. A police officer parked on the site was found to effectively reduce traffic speeds and should be used if available and feasible. The research findings also suggest using a combination of temporary reduced speed limit signs, radar speed monitoring display, and PCMS on both trailers and rollers. Further research is needed to validate the research findings and better identify the advantages of one traffic control device over another.