Influences during adolescence on perceptions and behaviour related to alcohol use and unsafe driving as young adults

To investigate whether aggression, parent and peer influences, and previous traffic-related experiences at ages 15 and 18 impacted on (a) differences between the perceived safe and estimated legal alcohol consumption limit, and (b) driving while impaired (DWI) behaviour at age 21.

The study population was a birth cohort involved in a longitudinal investigation of health and development. At the ages of 15 and 18, study members completed questionnaires assessing parent and peer attachment, experience travelling with an alcohol impaired adult or youth, aggression, and previous crash experience. At age 21, study members were questioned about how much alcohol they perceived they could drink and still drive safely, and whether they had driven after 'perhaps consuming too much alcohol'. For each participant their legal alcohol consumption limit was estimated using their height and weight. Path analysis was used to determine whether variables measured at ages 15 and 18 predicted differences between the perceived safe and estimated legal alcohol consumption limit and driving while impaired, both measured at age 21.

Insufficient females drove while impaired at age 21, who also had complete data on all other variables, to conduct path analysis for this outcome. For males, aggression at ages 15 and 18, travelling with an impaired youth at age 18, and previous crash experience at age 18 predicted DWI behaviour at age 21. Only aggression at age 15 predicted the difference between perceived safe and estimated legal alcohol consumption limit for the males. For females, aggression at ages 15 and 18, and travelling with an impaired adult at age 15 predicted the difference between perceived safe and estimated legal alcohol consumption limit.

The results show that aggressive behaviours and adult and/or youth modelling of drink driving behaviours in mid- to late-adolescence are related to differences between perceived safe and estimated legal alcohol consumption limit for both genders and driving while impaired for males.