Unplanned drinking predicts alcohol-impaired driving cognitions and behavior in daily life.

Objective: This study used ecological momentary assessment to investigate the association between unplanned drinking and alcohol-impaired driving (AID) cognitions and behavior among adults.

Method: Adults (N = 125) completed 6 weeks of morning and evening ecological momentary assessment surveys assessing plans to drink later that night, driving behavior, and AID cognitions. Mixed-effects models with moments (Level 1) nested within days (Level 2) within person (Level 3) were used to test the effect of planned (vs. unplanned) drinking intentions on perceived danger of AID and willingness to engage in AID. A separate two-level model (days nested within person) tested planned (vs. unplanned) drinking on AID behavior. A novel breath alcohol concentration biosensor accounted for alcohol consumption in all models.

Results: Unplanned drinking episodes were associated with lower perceived danger of AID, increased willingness to engage in AID, and higher odds of engaging in AID, compared to planned drinking episodes. Findings were held after controlling for alcohol consumption measured by breath alcohol concentration biosensors.

Conclusions: Findings suggest that unplanned drinking intentions confer risk for AID-a behavior requiring significant preparation and planning to avoid. Findings highlight the need for future research investigating unplanned drinking's effect on other negative consequences requiring preparation and planning. Additionally, findings highlight the need for targeted interventions and policies to reduce unplanned drinking to prevent AID and improve public health outcomes among adults. (PsycInfo Database Record (c) 2025 APA, all rights reserved).