Event-Level Predictors of Alcohol-Impaired Driving Intentions

Alcohol-impaired driving is a significant public safety concern and is highly prevalent among young adults. Considerable research has examined between-person predictors of alcohol-impaired driving, but there has been little research on factors that predict alcohol-impaired driving at the event level. This pilot/feasibility study was designed to identify within-person, event-level predictors of alcohol-impaired driving intentions in the natural environment using an ecological momentary assessment (EMA) design.

Thirty-six young adult, moderate drinkers (M age = 22.9 years; 72.2% female; M drinks per occasion = 3.2) were recruited from a university area to complete 2 weeks of EMA. They reported on their subjective levels of intoxication, perceived dangerousness of driving, and driving intentions during real-world drinking episodes. Breath alcohol concentrations were collected with a portable breath alcohol analyzer.

Event-level perceived danger and subjective intoxication most strongly predicted intentions to drive after drinking, such that higher perceived danger and intoxication predicted lower willingness to drive, after adjusting for baseline alcohol-impaired driving attitudes (ps < .001). When we accounted for perceived danger during drinking episodes at the event and person level, baseline attitudes were no longer predictive of willingness to drive. Higher event-level breath alcohol concentration also predicted lower willingness to drive (p = .003).

This study is the first to demonstrate that event-level risks of alcohol-impaired driving can be collected during drinking episodes in the natural environment. Findings indicate that subjective perceptions of intoxication and risk more strongly predict alcohol-impaired driving intentions than objective intoxication. Findings also suggest that event-level perceptions of intoxication and driving risk may be fruitful targets for interventions to reduce alcohol-impaired driving.