Influence of Truck-Mounted Radar Speed Signs in Controlling Vehicle Speed for Mobile Maintenance Operations: Oregon Case Study

Radar speed signs (RSSs) are a measure for reducing traffic flow speeds through work zones. The influence of truck-mounted RSSs on vehicle speed was evaluated for mobile maintenance operations in two multilane maintenance work zones in Oregon. In each case study, two periods of testing were conducted: one with the RSS display turned on (treatment) and one without the RSS display turned on (control), and vehicle speeds were recorded. Descriptive statistics were used to summarize collected data, and a two-sample t-test was applied to each case study to compare the speed difference between control and treatment cases. The findings indicate that vehicle speeds are typically lower and that there is less variation in speeds between adjacent vehicles with the RSS turned on. RSSs are thus promising devices for controlling vehicle speed and making work zones safer for motorists and workers.