The negative role of alcohol in vehicular traffic has been recognized for a long time, as documented by epidemiological and experimental research in several countries. The problem of drugged driving has received considerable attention. Any registration of the frequency of the occurrence of a phenomenon in the total population of part of it can be considered to represent some form of epidemiological knowledge. Descriptive epidemiological studies simply measure the frequency of drug use in certain groups of drivers, by means of questionnaires, interviews or analysis of drugs in body fluids. From the literature, it appears that six groups of non-alcohol drugs have been studied by experimental and epidemiological methods to a degree that allows some conclusion with respect to their traffic safety hazard to be drawn. In a study on 1882 fatally injured drivers, K,.W. Terhune et al. carried out a responsibility analysis to assess the contribution of drugs to accidents.