Previous research has identified college students as a population at high risk for alcohol and other drug (AOD)-involved driving. A new study investigated the continuity of AOD-involved driving four years beyond college. Participants were a subset of the College Life Study, a prospective study of 1,253 individuals who were recruited as first-year college students in 2004. Most analyses in the present study included only individuals who reported having access to car in the past year. Students who screened positive for illicit drug use or prescription drug misuse at least once during high school were oversampled. Participants completed eight annual personal interviews throughout the study; AOD-involved driving behaviors were retrospectively assessed in Years 2-8. Measures of interest included past-year frequency of AOD-involved driving (driving while intoxicated [DWI], driving after drinking [DAD], and drugged driving [DD]), substances used during AOD-involved driving episodes, and past-year frequency of alcohol and marijuana use. Importantly, the researchers did not specify the distinction between DWI and DAD and students were left to subjectively interpret these terms. The authors used statistical weights to generalize findings from the sample to the general college student population. Trends were evaluated using a series of logistic models. Results found the prevalence of DAD increased significantly during college, then plateaued around Year 5. DAD was the only behavior that showed no significant declines throughout the study period; both DAD and DD peaked at modal age 21 (Year 4). Among the 863 individuals with complete data through Year 8, an estimated 43% reported DWI at least once, an estimated 63% reported DAD and an estimated 23% reported DD. Among participants who reported engaging in binge drinking, the probability of DWI peaked at 41% in Year 6, but among moderate-to-light drinkers, there was a stable trend of around 10% during Years 2-3, followed by a second stable trend at around 18% throughout Years 4-8. Among marijuana users, likelihood of DD exhibited an inverted U-shaped trend, with a significant decline from 46.2% in Year 5 to 37.0% in Year 8 (p = 0.029). The prevalence of binge drinking and marijuana use both stabilized at the beginning of the study period, then declined steadily. In any given year, the majority of participants who engaged in AOD-involved driving persisted in this behavior during the following year. The proportion of DWI drivers who also engaged in DD ranged from 54.9% in Year 2 to 32.8% in Year 8, while 45.8% – 58.8% of DD drivers engaged in DWI.
Take away: Although the reported prevalence of substance use declined over time, participants’ likelihood of driving while intoxicated (DWI) depended on their drinking patterns and did not necessarily decrease. Reported past-year drugged driving was common among participants who engaged in DWI, and vice-versa, across all years.