Drivers often experience difficulty accurately detecting the distance and direction of approaching on-call emergency vehicles (EVs). This study evaluates the effects of an in-vehicle advance warning device (AWD) on the safety of driver interactions with EVs. The AWD uses visual and auditory warnings when the EV was within a 300- to 400-m radius of the vehicle. An experimental study using an advanced driving simulator examined the effects of the AWD on driving performance in a range of circumstances in which real-world EV crashes and near-misses commonly occur. Each event contained a combination of scenario type (adjacent lane, turning across, car following) and warning condition (control, standard, advance). Data from 22 participants were collected, including measures of speed, braking, and visual scanning. Results show that the AWD was associated primarily with reductions in mean speed for adjacent-lane and turning-across events. The AWD also resulted in an earlier lane change to clear a path for the EV in the car-following event. The reduction in speed observed was a positive finding, given the relationship between impact speed and injury severity. Response priming emerged as the likely mechanism underpinning these benefits. Although further research is needed, a combined use of in-vehicle and out-of-vehicle warning systems offer the potential to improve driver interactions with EVs.
Abstract