On September 30, 2015, the (US) Governors Highway Safety Association [GHSA] published Drug-Impaired Driving, a report authored by Dr. Jim Hedlund, formerly a senior official with the National Highway Traffic Safety Administration [NHTSA], assisted by an advisory panel of experts from US state and national traffic safety organizations.
The need for such a publication had been noted in an open forum on drugged driving at GHSA’s 2014 Annual Meeting. Funding for its preparation was provided by the (US) Foundation for Advancing Alcohol Responsibility.
The key sections of the 51-page report address defining and understanding the extent of the problem of drug-impaired driving, the existing laws and law enforcement regimes addressing it, and the need for educational, law enforcement, and research and data collection programs.
Media reports have focused on the highlights: that drunk driving rates are declining while drugged driving rates are increasing and that, “In 2013, the most recent year for which data are available, NHTSA’s Fatality Analysis Reporting System (FARS) reported that drugs were present in 40% of the fatally-injured drivers with a known test result, almost the same level as alcohol.
NHTSA’s 2013–2014 roadside survey found drugs in 22% of all drivers both on weekend nights and on weekday days. In particular, marijuana use is increasing.”
The report is clearly written, well-summarized, and well worth review by teenagers and their parents, teachers, emergency responders including police, and lawyers who deal with motor vehicle cases.
Of particular note is the examination of the myth, widely believed, however, that marijuana doesn’t impair drivers, and in fact improves their driving. The report noted as follows:
• In Colorado and Washington States, where, as of August 2015, marijuana possession and use have been decriminalized, most regular marijuana users who were surveyed “drove “high” on a regular basis. They believe they can compensate for any effects of marijuana, for instance by driving more slowly or by allowing greater headways. They believe it is safer to drive after using marijuana than after drinking alcohol.”
• In Australia, many young drivers “were not aware that drugs can impair driving. Many believe that drugged driving was safer than alcohol-impaired driving or that drugs improved their driving.
• In Canada, young drivers “had similar views: drugged driving is less risky and less easily detected than alcohol-impaired driving; in particular, marijuana use does not impair and may improve their driving.”
This myth persists partly because the issues involved in studying the crash risk of drugs are complex: for example the need to control for other factors that affect crash risk; and the fact that most crash data record only drug presence rather than drug concentrations. The report asserts, however, the following “defensible conclusions” regarding drugs and crash risk:
• Any drug may increase a driver’s crash risk.
• The effect of any drug varies substantially between drivers.
• The effect of any drug increases as its concentration increases.
• Most illegal drugs and marijuana may at least double a driver’s crash risk.
• Some individual drugs, multiple drugs, and drugs combined with alcohol increase crash risk substantially.