Objective: Motor accidents caused by older drivers have been increasing and may result from a decline in cognitive functioning and delay in hazard perception. This study examined how brake operation and palmar perspiration indicate hazard predictive ability of older drivers in a driving simulation.

Method: We compared brake operation performance, palmar sweating response, and skin potential reflex responses in healthy older adults ( n = 43) and healthy young adults ( n = 36) during hazard and hazard prediction scenes in a driving simulator.

Results: In the hazard scene, both groups displayed rapid brake operation and skin potential reflex responses. In the hazard prediction scene, all young adults braked consistent with simulation footage, but 46.5% of older adults failed to brake. Palmar sweating response was greater ( p < 0.01) in older adults who braked compared to older adults who did not. In those who failed to break, palmar sweating response was lower than the overall average observed in the older adult group, suggesting that non-operating group members lacked a sense of tension.

Conclusion: Cognitive processes of hazard perception and hazard prediction may facilitate the observed increase in palmar sweating response. Brake operation monitoring and palmar sweating response measurement appear to be useful for evaluating hazard perception ability in a driving simulator.