The Safety Impact of Additional Blue Lights of Rescue Vehicles

The high crash risk particular during emergency drives has been reported in numerous studies. The BRK endeavors to decrease the crash frequency of their ambulance vehicles by improving their visibility especially at intersections and narrow gateways. Therefore, additional side flashing lights have been proposed. The purpose of this study is to evaluate the effectiveness of these flashing lights. In this context, emergency drives conducted with equipped and unequipped ambulance vehicles were compared. More precisely, the exit of a BRK station and the adjacent road segment was observed for 14 days by a video camera, which enables computer-vision aided analysis of the traffic. Within this time frame, 38 traffic situations of unequipped and 13 situations of equipped ambulance vehicles were observed. The trajectories of interacting road users in these situations were analyzed. Indicators for the adaption of road users to ambulance vehicles leaving the BRK station were used, like deceleration, position and time of braking as well as time of reaching walking speed.

The indicators showed, that road users entered the observation area slower encountering equipped ambulance vehicles-probably due to prior braking-than was measured at emergency drives without additional flash lights. Furthermore, road users on average were breaking 3.5 meters earlier, less intensely and reached walking speed 4 meters earlier when ambulance vehicles were equipped with additional flash lights. The interpretation of these results is that earlier reaction implies earlier perception of the ambulance vehicle.