The self-reported psychosocial and legal factors contributing to drink and drug driving

Drug driving is recognised as a major road safety problem in many countries. In Australia, the primary response to this problem involved the adoption of roadside drug testing (RDT), which was modelled on the policies and practices used to conduct random breath testing (RBT) for alcohol. However, there remain important differences in the way that RDT and RBT are conducted, which might produce differential effects on drug and drink driving behaviour. In addition, various psychosocial factors are known to influence the two behaviours. Thus, there is a need to investigate the relative influence of legal and psychosocial factors on drug driving and explore how they may be similar or different to drink driving. Accordingly, this study utilised Deterrence Theory and Akers' Social Learning Theory, augmented by measures of dependence and a range of psychosocial factors, to examine the factors associated with self-reported drink and drug driving. An online survey was completed by 1394 licensed drivers from the three most populous states in Australia: Queensland, New South Wales and Victoria. Self-reported drink and drug driving became more likely as level of dependence increased. In relation to legal factors, direct experience of avoiding detection was the strongest predictor of self-reported drink and drug driving. Among the psychosocial factors, a significant positive relationship was found between holding favourable attitudes toward both drink driving and drug driving and self-reported behaviours. The findings suggest that applying legal sanctions in isolation without addressing the psychosocial rewards and punishments for the behaviours is not sufficient to reduce drug or drink driving. Future research should identify countermeasures that integrate deterrence and psychosocial principles in order to reduce these risky driving behaviours.