Within-Person and Between-Person Risk Perceptions Predict Driving After Drinking: An Ecological Momentary Assessment...

Alcohol-impaired driving (AID) remains a significant public health concern, accounting for approximately 30% of vehicle fatalities annually in the United States. Despite widely negative attitudes toward AID, many adults report driving after drinking. Day-to-day changes in how people think about AID may explain this inconsistency. This study used ecological momentary assessment (EMA) to examine how both stable patterns and day-to-day changes in perceived danger of driving, willingness to drive, and subjective intoxication predict real-world driving after drinking.

Participants (N = 113) from a Midwestern community completed six weeks of EMA data collection. Daily morning surveys assessed the previous night's drinking and transportation decisions, while repeated evening surveys measured perceived danger of driving, willingness to drive, subjective intoxication, and breath alcohol concentration (BrAC) using portable breathalyzer devices. Mixed-effects models examined day- and person-level cognitions as predictors of driving behavior while accounting for alcohol consumption via BrAC.

Participants reported driving on nearly half of drinking days. On days when people perceived driving as more dangerous and felt more intoxicated than usual, they were less likely to drive. Moreover, on days when people were more willing to drive than usual, they were more likely to drive. These patterns held after accounting for BrAC. Additionally, people who typically experience stronger subjective effects of alcohol were less likely to drive on days when their breathalyzer readings were high (BrAC ≥ 0.05%).

Day-to-day changes in how people perceive the dangers of driving and how intoxicated they feel predict whether they drive after drinking, even at high BrAC. People who typically experience strong subjective effects from alcohol appear especially responsive to objective indicators of high intoxication levels. Findings support developing real-time interventions that combine subjective feelings of intoxication with objective measures such as breathalyzers to promote safer transportation choices.

ClinicalTrials.gov: NCT03846050.