The Report of the National Commission on Marihuana and Drug Abuse

Marihuana and Driving

TTHE CURRENT STATE OF KNOWLEDGE

The literature on drugs and driving contains several references to the role of drugs, including marihuana, in traffic violations, accidents and fatalities. They differ considerably, however, in the nature and extent to which they influence or affect driving behavior (Waller, 1965; Chetta, 1967, Commission on Narcotic Drugs, 1968; Third Triannual Congress on Traffic Accidents, 1969; Waller, 1970; Klein, Davis and Blackbourne, 1971 National Institute of Mental Health, 1972).

The studies examine the relationship between marihuana and driving and tend to be either statistical and enumerative with regard to traffic accidents or experimental with respect to the physiological and psychological effects of marihuana use deemed to be related to driving skill and performance. All of them suffer to one degree or another from an overabundance or dearth of extraneous variables and have, therefore, precluded generalization of the results and the production of conclusive, and valid findings.

The difficulty in interpreting the data gathered from statistical or enumerative studies of traffic accidents derives primarily from the inability to isolate precise cause. There are no tissue, urine or blood analysis methods currently and systematically in use outside the laboratory, similar to those available for alcohol, for determining the presence of marihuana in the bodily fluids of drivers.