The report is divided into three sections covering the incidence of drug use by: (1) fatally injured drivers, (2) injured drivers, and (3) nonaccident involved drivers detained by the police. The studies reviewed indicate which drugs are being used by drivers. The drugs (or drug classes most frequently detected are (in order of decreasing incidence): marijuana, Diazepam (Valium(R)), cocaine, barbiturates (e.g., secobarbital), methaqualone, and PCP (phencyclidine). The data reviewed indicate that drugs are detected in 10 percent of the accident involved drivers. The majority of the drug-using drivers were found to have high levels of alcohol in combination with the drugs. Tables and 25 references. (Author abstract modified)