On 17 December 1982, random breath testing (RBT) was introduced in New South Wales (NSW). RBT was a radical departure from previous drink-driving enforcement campaigns in NSW, general deterrent philosophy, in contrast to the traditional approach emphasizing the detection and punishment of offenders. The incorporation of nonlegal sanctions in the model highlights the importance of the physical and social environment. It has been assumed that in the absence of nonlegal norms, changes in behavior caused by a legal intervention must be due to the operation of deterrence. The need to invert one's perspective when studying drinking and driving is one reason why study of the offense can make a useful contribution to the development of the rational choice perspective. It could be argued that drinking and driving is one of a class of "less serious" offenses for which opportunities arise frequently as a natural part of social interaction rather than being sought out by the potential offender.