The use of mind-altering drugs other than alcohol presents a serious contemporary problem. Some people are concerned about the real effects of drugs on users, others about perceived effects which at times seem to bear little relationship to pharmacologic reality. Many are aroused primarily because they see in drug use a symptom of widespread moral and religious decay. A few are worried largely because they fear that drug users may commit acts which harm innocent nonusers. All of these concerns are important in considering the role of mindaltering drugs in the occurrence of highway crashes, because these concerns have largely determined our perception of the problem of drugs and highway crashes. At times, they have led to preventive and corrective actions that not only are inappropriate but often sap away scarce funds and effort that should be devoted to more effective solutions. In this communication the following questions are explored: