Objectives: Ethanol is well-known to impair driving ability. The major aim of this study was to evaluate the number of
drivers driving under the influence of ethanol in a population of randomly controlled drivers.
Methods: 1016 drivers were randomly controlled at 27 different locations in Western Switzerland from October
2006 to April 2008. Drivers were controlled for alcohol consumption with a breathalyzer according to the
Swiss Road traffic law. If the result was equal or higher than an equivalent of a blood alcohol concentration
of 0.8 g/kg, a blood sample was taken; otherwise, a saliva sample was obtained.
Blood and saliva were analysed for ethanol by Head-space gas chromatography coupled with a FID detector.
Results: Among the controlled drivers, men (69%) predominated over female (31%). The mean age was 41 (range:
16 90). For 968 drivers (95.3%) ethanol was not detected in blood or saliva. These drivers were not under
the influence of ethanol. Ethanol was detected in saliva or blood of 48 drivers (4.7%). Among these drivers,
blood alcohol concentration (BAC) was above the legal limit of 0.8 g/kg (serious offence) in 14 cases
(1.4% of the total population). BAC were in the range of 0.91 to 2.43 g/kg (mean: 1.32 g/kg, median: 1.11
g/kg). Among these 14 cases, men (13 cases, 93%) were over represented. No ethanol was found in the population
of truck drivers (17 cases). 986 drivers were car drivers and 46 of them have drunk ethanol (5%).
13 bikers were controlled and 2 of them have drunk ethanol (15%).
Conclusion: Driving under the influence of ethanol concerned about 5% of a population of randomly controlled drivers,
and 1,4% of the drivers had a blood alcohol concentration higer than 0.8 g/kg (legale limit for a serious
offence).