Short-term reliability of a brief hazard perception test.

Hazard perception tests (HPTs) have been successfully implemented in some countries as a part of the driver licensing process and, while their validity has been evaluated, their short-term stability is unknown. This study examined the short-term reliability of a brief, dynamic version of the HPT. Fifty-five young adults (Mage=21 yrs) with at least two years of post-licensing driving experience completed parallel, 21-scene HPTs with a one-month interval separating each test. Minimal practice effects (∼0.1s) were manifested. Internal consistency (Cronbach's alpha) averaged 0.73 for the two forms. The correlation between the two tests was 0.55 (p<0.001) and correcting for lack of reliability increased the correlation to 0.72. Thus, a brief form of the HPT demonstrates acceptable short-term reliability in drivers whose hazard perception should be stable, an important feature for implementation and consumer acceptance. One implication of these results is that valid HPT scores should predict future crash risk, a desirable property for user acceptance of such tests. However, short-term stability should be assessed over longer periods and in other driver groups, particularly novices and older adults, in whom inter-individual differences in the development of hazard perception skill may render HPT tests unstable, even over short intervals.