Performing roadway construction work at night exposes workers to hazards that are not present or as great during the daytime. Working at night requires illuminating the area where work is taking place in order to provide sufficient lighting for the workers to see their work and to illuminate the workers. Work area lighting may also have a positive impact on the speed of passing vehicles. Based on previous studies (e.g., SPR 751 and 769) vehicle speed reduction in the work zone during nighttime operations is assumed to be due in part to the lighting provided to conduct the work. The present study evaluated the impact of temporary work zone lighting on vehicle speeds. The study includes case studies on multi-lane preservation projects in Oregon in which different types of lighting systems were implemented: a light tower, balloon light, and a personal, wearable light. The research findings indicate that additional temporary roadway lighting helps to make workers more visible to motorists and equipment operators, and leads to slightly higher vehicle speeds. Implementation of additional temporary roadway lighting is recommended where the work operations contain concerns regarding visibility. Personal, wearable lights are also recommended for workers who are located away from large equipment and other light sources.