Driving a car under the influence of alcohol in Germany: Results from a trip-based self-report measurement

Driving under the influence of alcohol comprises a serious road safety issue. A comprehensive investigation is challenging and a high number of unreported cases of driving under the influence of alcohol is suspected. Existing methods, including roadside surveys or period-based self-reports, are either difficult to implement or may lack informative value.

This paper describes a newly developed questionnaire-based survey conducted in a nationwide online survey in Germany that measures the prevalence of driving under the influence of alcohol via self-reports concerning randomly selected trips from 7 days prior. The trip-based data collection includes details about the reported car ride. Expected low case numbers are addressed by additionally recording the last trip driven under the influence of alcohol from the previous week.

Within the previous 7 days, 6.3% of the surveyed drivers had driven under the influence of alcohol. Further analyses aligned with familiar patterns from prior research: Age, sex, daytime, and days of the week significantly predict driving under the influence of alcohol. However, attitudes toward stricter rules are also identified as a factor.

The proposed survey design enables the current findings to surpass results of previous surveys and yields data comparable to roadside survey results. The questionnaire proved feasible in conducting the survey and gathered valid findings that correspond to international research and traffic crash data. For Germany, in particular, and in alignment with familiar patterns related to times and days, the findings point to the likelihood that particularly males and younger drivers will drive under the influence of alcohol.

The proposed survey concept adds a new variant to the set of instruments for recording driving under the influence of alcohol by determining a trip-based prevalence, thus offering new insights into driving under the influence in alcohol of Germany.