The Effect of Novel External Communication Display on Pedestrian Judgements of Acceleration

Pedestrian fatalities are on the rise in the United States, and this trend shows no signs of reversing. One contributing factor to these incidents is pedestrians' difficulty in accurately assessing traffic conditions and vehicle actions, leading to potentially fatal collisions. One promising solution could be the use of additional visual cues through external vehicle lighting on the front of vehicles to aid pedestrians in making safer decisions. This research explored this possibility through two studies that examined an LED display mounted on the grill of a study vehicle. The display changed color to communicate whether the vehicle was accelerating or decelerating (the display turned white if the vehicle was accelerating, and amber if the vehicle was decelerating). The first study assessed how well participants could judge whether the vehicle was accelerating or decelerating when the display was active versus inactive, and whether a verbal explanation of the display's function improved their understanding. The second study not only revisited judgement accuracy, but also examined its influence on participants' crossing intentions. Additionally, this study evaluated if repeated exposure to the display in a different traffic scenario (maneuvering a left turn at a stop sign controlled intersection) enhanced understanding as well as verbal explanations, which are less feasible in real world traffic situations. Findings from these studies indicated that a clear verbal explanation of the display significantly enhanced participants' ability to discern vehicle acceleration and deceleration, but exposure to the display in other traffic scenarios provided the same benefit. Study 2 did not observe significant changes in the safety buffer (i.e. the amount of time between when participants decide to cross, and when there would be a conflict with the vehicle if they did cross), but the average number of safe crossing decisions versus unsafe was improved, though these results were inconsistent across participants. These findings suggest potential for enhancing pedestrian safety by providing pedestrians with additional information through external vehicle lighting displays. Future research should focus on optimal implementations strategies for such displays and investigate any possible unintended consequences of deploying this technology on public roads.