Use of Flashing Amber-White Lights on Paving Equipment in Work Zones

Safety treatments to mitigate speeding inside work zones is of perennial interest among construction partners. Prior research by ODOT and OSU captured the effect of flashing blue lights on speeding behavior. This study extended that effort to evaluate flashing amber and white lights. Three case studies were conducted on Interstates 5 and 205 during nighttime construction. Using traffic sensors placed on the roadway and GPS sensors placed on paving equipment, vehicle speed, type, volume, headway, and location were recorded. Speed reduction inside the work zone, and speed differential between the road work ahead (RWA) sign and the paver location, were compared statistically using two sample t-test. Results show significant speed reduction for the flashing amber-white lights used in Case Study 2 (2.5 to 10.1 mph inside the work zone, and 1.5 mph between the RWA sign and the paver location). Flashing amber lights showed a speed reduction between the RWA and the paver location in Case Study 1 (4.1 mph). No meaningful difference was observed in Case Study 3. Flashing amber-white lights are recommended for better identification of the paving equipment. Comparison with flashing blue lights suggested a greater impact on speed behavior using the flashing blue lights.