The introduction of compulsory blood alcohol tests on road crash casualties 15 years of age and older has provided hospital material for the study of alcohol related crashes and road trauma.A 2 year study of two major emergency departments in Melbourne hospitals was undertaken (1981-1982). Patients found to be alcohol positive (n.654) were matched against an equal number who were alcohol negative. Road user and licence status, blood alcohol level, injury patterns were studied as well as the demographic variables of age, sex, marital status and occupation. The study found significant differences existed in the variables between the two populations. The level of medical staff co-operation was fair. It is suggested that some changes to the overall system are required if the aims of the legislation are to be achieved.