Parking behaviour under the influence of alcohol

Real-life driving studies evaluating the impact of alcohol influence on the ability to park a car are rare but necessary to assess a possible impairment to drive a car in the event of prosecution. In this study, 29 test persons (13 m, 16 f) completed three test drives with real cars, each made up of three different parking situations. While four test persons remained sober, the majority drank a previously calculated amount of alcohol before the second drive; the aim was to reach a blood alcohol concentration (BAC) of 1.1 g/kg. The third drive took place about 2 h later without any further ingestion of alcohol. The impact of BAC on the number of accidents, time needed to finish the drive, the amount of correction moves and quality of the final parking position (in the centre of the parking space) were analysed. Furthermore, pressure measuring films were applied to the test cars, measuring the average pressure and load in the areas of the accident impact. A significant increase of accidents could be noted with rising BAC. While a single accident happened to both sober and drivers under the influence of alcohol, more than one accident was only seen in drivers after the ingestion of alcohol (> 0.63 g/kg). The BAC had no impact on the other considered aspects. Concludingly, more than one impact site or accident while parking a car can serve as an indication for alcohol impairment of the driver at the time of the accident.