Five focus groups (36 participants in all) and a field survey (160 participants) were used to investigate the perceptions and behavior of drivers who used illicit opiates, stimulants, and cannabis. The participants were aware of many drug effects that may impair driving ability, but they believed they were not at significantly increased risk of accidents. For many participants, drug use was closely linked to driving; most of the heroin and amphetamine users drove to purchase their drugs and frequently used drugs inside a car. Some of the amphetamine users who deliberately drove after taking the drug reported alarming attitudes and behavior. Few participants were concerned about the illegality of their driving behavior, and nearly 10 percent were driving without a license. Heroin users perceived drug-induced tiredness as an accident risk and reported frequently experiencing this condition. Altering drug-driving behavior is likely to be difficult, given drug dependence for some users and heavy reliance on private motor vehicles for transport in Melbourne, but also because of conflicting scientific evidence that links impairment to the use of most illicit drugs. 4 tables and 19 references