Basic traffic accident data describing the numbers, cost, baselines, and day/night distribution of alcohol and drug-related traffic accidents are presented in tabular form to lay the foundation for subsequent discussion. Perception, recognition, and decision errors, as well as other human factors in traffic accidents are detailed, and various measurement devices used in performance testing are described. Methods of dealing with the drinker who drives are then discussed. The problems of calculating the legal limits of intoxification are first considered, and the effectiveness of various devices used in measuring intoxification degree is evaluated. Educating the individual driver on his/her own state of performance impairment after alcohol consumption is suggested, and a number of techniques that might be used to reduce alcohol-related traffic accidents are proposed, including the prohibition of alcohol advertisements, increasing the tax on alcoholic beverages, lowering the alcohol concentration in commercial beverages, and increasing the public's awareness of the carcinogenic effects of alcohol. The effects of drugs and alcohol on driving performance are compared, followed by a discussion of the extent of drug use in the United States, along with methods for analyzing the ways in which drugs impair driving performance. Major medical conditions that affect driving performance are also considered. In the final chapter, recommendations for program development and future research in traffic safety are presented in discussions on accident survival rate, decreased emphasis on enforcement, the social drinker, the problem drinker, the hazards of smoking cigarettes while driving, and other major concerns in the drug/driving field. (Author abstract modified)