Abstract
Previous studies found age-related differences in judging time to contact (TTC), assuming the occurrence of impending collision events. DeLucia et al. (2003) pointed out that judgments of the occurrence of collisions should be made prior to judging when collisions would occur. Andersen and Enriquez (2006) found age-related declines in collision detection sensitivity, particularly for increased speed, shorter display durations, and longer TTC conditions. One important question remains unclear is whether the vehicle's speed would affect a drivers' sensitivity to collision events. In the current study, we examined the effect of ego-speed on collision detection between younger and older observers. The constant expansion rate information was achieved by keeping the relative speed between object and observers constant. The independent variables include display duration (3 or 7 sec with constant TTC of 9 sec) and ego-speed (24, 36, or 48 km/h). 22 younger adults (mean age of 20.3) and 21 older adults (mean age of 79.1) participated in the experiment, in which they were presented with displays simulating a single approaching object in the 3D scene. The results showed declines in collision detection sensitivity for older observers, as compared to younger observers, particularly with decreased display duration and increased speed. However, older adults performed as well as younger adults in longer display duration (7 sec) even at high ego-speed (48 km/h). Overall, the results suggest older observers have more difficulty detecting collision object within limited time, as compared to younger observers, particularly at high ego-speed. In other words, older drivers need more time to successfully detect an imminent collision object, which indicates less time is left for them to take effective controls thus resulting in increased crash risks.
WSU RIA Gridley-Hoover Grant.