Driving under the influence of alcohol in the Netherlands by time of day and day of the week

• Drink driving is not only limited to night-time hours.
• Drink driving also occurs early in the morning and early in the evening on weekend days.
• Some drink drivers were detected during rush hour on Monday and Friday mornings.
• We advise that breath testing activities should also take place outside night-time hours.

The purpose of this study is to provide an overview of the variation in the prevalence of alcohol in everyday traffic in the Netherlands during all days of the week and all times of day. Breath tests were taken from randomly selected car drivers and drivers of small vans in six police regions in the Netherlands between January 2007 and August 2009. A total of 28,057 drivers were included in the study. The prevalence of driving under the influence of alcohol was highest during night-time hours of weekend days. Large proportions of sampled drivers under the influence of alcohol were also found during day-time hours on weekend days, especially early in the morning and early in the evening. Furthermore, a small proportion of sampled drivers under the influence of alcohol was found during morning traffic on Monday and Friday mornings. The results of this study indicate that drink driving is not only limited to night-time hours and that prevalence of drink driving is also high during evening hours from Wednesday to Sunday. In addition to these time periods, breath testing activities may also be effective from a police enforcement perspective on Monday, Friday, and Saturday mornings between 06.00 h and 08.00 h and on Sunday mornings until 10.00 h.