The factors associated with preferences for napping and drinking coffee as countermeasures for sleepiness at the wheel among Japanese drivers.

OBJECTIVE We explored differences between professional and non-professional drivers in terms of the factors associated with preferences for generally accepted, effective countermeasures for sleepiness at the wheel--i.e., napping and drinking coffee. METHODS We performed a cross-sectional questionnaire survey. Data from professional (n = 716) and non-professional (n = 3365) drivers were used for analyses. RESULTS The results showed that professional drivers experienced drowsy driving and traffic accidents due to falling asleep more often than non-professional drivers. Multiple logistic regression analyses showed that variables which may act as aggravating factors for sleepiness (i.e., engagement in shift-work and insufficient sleep) were associated with preferences for these countermeasures among non-professional drivers. In contrast, among professional drivers, being male and having experienced traffic accidents due to drowsy driving were associated with a preference for napping, while longer annual driving distances and shorter periods after the acquisition of driving licenses were associated with drinking coffee. CONCLUSION Our results suggest that non-professional drivers are likely to take these effective countermeasures when they feel or have the potential to experience sleepiness at the wheel. However, this tendency was not observed in professional drivers, and it is speculated that they do not use naps as a countermeasure until they have experienced traffic accidents due to drowsy driving. Sleep education for professional drivers and their employers is desirable for preventing drowsy driving-related traffic accidents.