Biological and behavioral factors affecting driving safety.

The authors examine how motor vehicle crash involvement risk increases with driver lifestyle features, such as drug and alcohol intake; individual characteristics, such as gender and age; and driving safety-related human factors. The probability of road accidents increases among young male subjects with aberrant driving behaviors (driving speed, violations, alcohol abuse) who have particular personality traits (sensation seeking, aggressiveness). Falling asleep or drowsiness, usually affecting the driver in the early morning hours, is ascribed to a large proportion of traffic accidents. Sleepiness is affected by factors including driver chronotype, which may, especially at certain times of day, influence driving safety since individual sleep-wake cycle related variability has been associated with performance rhythm changes. Although there is a large amount of traffic accident literature, further research is needed to clarify the potential causative role of several factors the authors present an overview of (chronotype, personality traits, and others). In order adopt appropriate measures to increase driving safety, a better understanding of how motor-vehicle accidents are affected by human factors is required.