Research initiatives to improve the visibility and hence safety of road workers at night-time.

Collisions between vehicles and pedestrians represent a significant road safety problem and are overrepresented at night-time, with pedestrians being up to seven times more likely to be involved in a fatal collision at night than in the day [1]. This is particularly relevant at road work sites, which place road workers in a potentially vulnerable position with respect to oncoming traffic. Over the 1995 to 2002 period, 844 US workers were killed while working at a road construction site, and in over half of these fatalities the road worker was struck by a vehicle or moving equipment [2]. Fatal crash data also demonstrate that night-time construction is five times more hazardous than daytime construction [3]. Visibility and conspicuity issues may be key causative factors; analyses of crash databases have shown that the increased incidence of crashes involving pedestrians at night is primarily a consequence of reduced illumination rather than other factors that might vary between day and night, such as driver fatigue and alcohol use [1, 4]. This suggests that at night, drivers are often unable to recognize and respond to pedestrians from a safe distance [5].