Rijden onder invloed in de provincie Friesland, 1992-1993 : de ontwikkeling van het alcoholgebruik van automobilisten in weekeindnachten. In opdracht van Directoraat-Generaal Rijkswaterstaat, Adviesdienst Verkeer en Vervoer AVV en Directoraat-Generaal Rijkswaterstaat, Directie Friesland.

In October 1993, the SWOV Institute for Road Safety Research and six police control teams conducted a roadside survey. The aim was to establish the motorists' alcohol consumption in the Dutch province of Friesland. Blood alcohol content (BAC), age and sex of the drivers were collected and recorded. If the recorded BAC level was 0.5 or over, places of origin of the offenders were also collected and recorded. The study was carried out on Friday and Saturday nights. The 1993 sample included 1420 motorists. The results of the 1993 survey are compared with the results of the 1992 survey