Since 1973, the alcohol consumption of drivers has been systematically studied.
Data is available about the percentage of car drivers with a BAC > 0,5‰, per province, and has, since 1993, also been available by age, sex, origin, police region, and time of day.
The purpose of the survey is to determine the alcohol consumption of motorists. To do this, every autumn a minimum of 1500 motorists per province are tested during weekend nights.
The data gathered is used to prepare policy, and to determine the effects of measures and policy areas needing special attention. Useful data also provided by the surveys concern police surveillance (enforcement strategy, procedures, and technical aids). Conducting such a survey is itself an efficient form of controlling the drinking and driving problem.
The police measure the blood alcohol contents (BAC) or breath alcohol contents (BrAC) of a random sample of moving traffic. The breath testing is done with digital breath testers that have been approved by the Dutch Forensic Institute (NFI) and the Ministry of Justice.
Besides the BAC or BrAC, the day, time of day, sex, age, origin, main region, province, and municipality size are also registered.
As the sample is large, it is also possible to monitor the national development of the percentage of drivers with an extremely high BAC (>1.3‰) and a consequently high accident risk.
Until 1999, the survey was carried out by SWOV, in the last year together with the Transport Research Centre (TRC) of the Ministry of Transport. Since 2000, TRC has carried out the surveys.
The data only concerns the alcohol consumption of car drivers. It provides, therefore, no insight into (for example) knowledge and attitude.
The sample is sufficiently large to pronounce upon developments at the national, provincial, and sometimes even ‘lower’ levels, such as police regions.
To do this, the total sample was enlarged in 1991. From then on, the drivers tested were no longer asked about their drinking and driving habits in detail. Nowadays this done in Traffic Test’s PROV-survey.
Mathijssen, M.P.M (1996). Rijden onder invloed in Nederland, 1994-1995
Ontwikkeling van het alcoholgebruik van automobilisten in weekendnachten. R-96-17. SWOV, Leidschendam.
AVV (2001). Rijden onder invloed in Nederland, onderzoek 2000. Ontwikkeling van het alcoholgebruik van automobilisten in weekendnachten. Directoraat-Generaal Rijkswaterstaat, Adviesdienst Verkeer en Vervoer, Rotterdam