Prevalence of driver sleepiness in a random population-based sample of cardriving

Study Objectives: To obtain reliable estimates of the prevalence of driver sleepiness. Design: A two-stage cluster sampling technique was employed to obtain a sam ple of car drivers representative of time spent driving on public roads in a geographically defined region. Data were collected by interviewer-adminis tered questionnaire, and analysed in accordance with the sampling design. Setting: The Auckland region of New Zealand, between April 1998 and July 19 99. Participants: 588 drivers of cars and other light vehicles recruited at 69 roadside survey sites. Measurements and Results: Of 746 eligible participants, 79% were interviewe d, 12% refused, 8% were untraceable, and 1% were unable to give informed co nsent. From this sample we estimated that 58.7% of driving was undertaken b y men. The vast majority of driving (90.8%) was undertaken by drivers with Epworth Sleepiness scores in the normal range (<10), but a significant mino rity was undertaken by drivers with one or more characteristics likely to i mpair alertness. 3.1% had <less than or equal to>5 hours sleep in the previ ous 24 hours, and 21.9% had less than or equal to4 full nights sleep In the previous week. The triad of symptoms associated with sleep apnea. (snoring , choking, and breathing pauses while sleeping) was present in 1.6%; and 8. 1% worked a pattern of shifts likely to interfere with normal sleep. Conclusion: The prevalence of sleepiness amongst a random sample of New Zea land car driving was low, and less than suggested by previous studies.