A new study found that drivers who test positive for drugs are three times more likely to be in fatal car accidents and this risk increases 23 times for drivers who test positive for both drugs and alcohol.
Drunk driving has been the focus of many scientific studies. However, this is the first time researchers have looked at implications of driving while under the influence of drugs.
In a new study, researchers from the Columbia University's Mailman School of Public Health looked at the association between driver drug use and fatal car accidents. They also looked into the link between such car accidents and drivers being under the influence of both drugs and alcohol.
Researchers used two national information systems sources sponsored by the National Highway Traffic Safety Administration: the 2007 National Roadside Survey of Alcohol and Drug Use by Drivers and the Fatality Analysis Reporting System (FARS) to gather data for their study.
They found that 31.9% of the drivers involved in fatal car crashes and 13.7% of the drivers interviewed in the roadside survey tested positive for at least one non-alcohol drug. They also noted that drivers who tested positive for drugs were three times more likely than those that tested negative to be in a fatal car accident. Among the drugs used, depressants posed the highest risk, followed by stimulants, narcotics, and marijuana.
Researchers also found that 57.0% of the drivers involved in fatal car crashes and 8.8% drivers interviewed at the roadside survey also tested positive in elevated blood alcohol levels. About one-fifth (20.5%) of the cases tested positive for alcohol and one or more drugs, compared with 2.2% of the controls. Researchers noted that the risk of being in a fatal car crash increased 13 times for those who tested positive for alcohol but negative for drugs. This risk factor increased 23 times for those who tested positive for both alcohol and drugs.
"The possible interaction of drugs in combination with alcohol on driving safety has long been a concern," said Dr. Li, who is also professor of Anesthesiology at Columbia. "While alcohol-impaired driving remains the greatest threat to traffic safety, these findings about drugged driving are particularly salient in light of the increases in the availability of prescription stimulants and opioids over the past decade."
