Random breath testing was introduced into Western Australia in October of 1988. The National Centre has collaborated with the WA Police Department and the WA Alcohol and Drug Authority in an evaluation of RBT two years after its introduction. The National Centre's contribution to this evaluation was to: 1. compare responses of drivers to two surveys, one conducted mid-1988 and the other in late 1990; 2. conduct an analysis of changes in various types of traffic accidents pre- and post-RBT in police regions with different methods of implementing RBT. The main interest in the latter analysis was to test the hypothesis that greater benefit would accrue in police regions with close to 100% testing of drivers stopped in comparison with regions who only test about a third of drivers stopped. Other sections of the evaluation concerned the extent to which RBT has been enforced statewide and also further pre- and post-survey data restricted to drivers aged 30 and above.