Two drinks and drive: Assessing the average driver’s ability to self-restrain from alcohol and drug use while driving

In this study, participants answered 7 questions about their ability to restrain from substance use while driving, as well as socio-demographic questions. A total of 360 non-offender drivers completed the questionnaires. Slightly more than half (51.8%) of the non-offender drivers admitted to driving after consuming 1 or 2 beers or glasses of wine. Moreover, 15% of drivers also said they had taken other drugs, including cocaine, amphetamines or designer drugs (8%), and medications that cause drowsiness. Additionally, experienced drivers showed a higher tendency to not restrain from substance use while driving compared to novice drivers. An important link was found between reports of driving shortly after consuming more than 3 beers or glasses of wine and an AUDIT diagnosis of either moderate risk or alcohol use disorder. Moreover, significant relationships were found between reports of driving after consuming cannabis, hashish or marihuana and an AUDIT and DAST diagnosis in addition to an affirmative response to the question about driving after taking drugs or non-prescription medications. Furthermore, drivers who reported driving after consuming 1 or 2 beers or glasses of wine also reported a higher number of accidents with material damage. The number of fines was also higher for those who reported driving after consuming 5 or more spirit drinks. Additionally, drivers who drink and drive also self-reported a higher rate of violations, aggressive violations, errors and lapses. Finally, unsafe behaviours, violations and errors were also associated with the use of a second substance, mainly cannabis.