Effect of Work Zone Lighting on Drivers’ Visual Performance and Perceptions of Glare

Nighttime crashes at work zones are a major concern for construction workers and motorists. Although a majority of the state department of transportations (DOT) specifications of work zone lighting in the United States mention that contractors should reduce glare from workers and drivers, only two states advocate detailed specifications like light positions, orientations, light levels etc. While some studies have examined the impact of glare from work zone lights on workers and others calculated veiling luminance levels for drivers in the work zone, the effect of work zone lighting on drivers’ visual performance and glare perception have never been studied in a realistic setting. The goal of this paper to understand the impact of the three types of commercially available portable light tower types (metal halide, light emitting diode and balloon) and their orientations on drivers’ visual performance, and their perceptions of glare. Participants drove through a realistic work zone simulated on the Virginia Smart Road. Visual performance was assessed by a detection task and perception of visibility and glare were assessed by questionnaires. Results indicated that the type of light tower and their orientation affect visual performance and perceptions of visibility and glare. The light tower orientation that is aimed towards the driver resulted in lowering drivers’ visual performance, both, objectively and subjectively. When the light towers are aimed away from or perpendicular to the driver, the visual performance was higher and the differences in visual performance between the types of light towers were minimal, indicating that these should be the preferred orientation for work zone light towers.