Mixing booze and pot is a serious threat to traffic safety

June 12, 2017, Columbia University's Mailman School of Public Health

June 12, 2017Use of marijuana in combination with alcohol by drivers is especially dangerous, according to a latest study conducted at Columbia University's Mailman School of Public Health. Drivers who used alcohol, marijuana, or both were significantly more likely to be responsible for causing fatal two-vehicle crashes compared to drivers who were involved in the same crashes but used neither of the substances. The findings are published in the journal, Annals of Epidemiology.

"The risk of crash initiation from concurrent use of alcohol and among drivers increases by more than fivefold when compared with drivers who used neither of the substances," said Guohua Li, MD, DrPH, professor of Epidemiology at the Mailman School of Public Health. The study also indicates that when used in isolation, alcohol and marijuana increase crash culpability by 437 percent and 62 percent, respectively.

The researchers analyzed data for 14,742 fatal two-vehicle crashes between 1993 and 2014 recorded in the Fatality Analysis Reporting System, a database containing information on crashes that resulted in at least one fatality within 30 days and that occurred on U.S. public roads. Included in the study were 14,742 drivers who were responsible for causing the and 14,742 non-culpable drivers who were involved in the same crashes. Crashes involving single vehicles, more than two vehicles, commercial trucks, and two-vehicle crashes in which both drivers were responsible were excluded from the analysis.

Drivers who were responsible for the crashes were significantly more likely than non-culpable drivers to test positive for alcohol (28 percent vs. 10 percent), marijuana (10 percent vs. 6 percent), and both alcohol and marijuana (4 percent vs. 1 percent). Drivers who tested positive for alcohol, marijuana, or both were more likely than those who tested negative to be male, aged 25 to 44 years, and to have had a positive crash and violation history within the previous three years.

The three most common driving errors that led to these fatal crashes were failure to keep in proper lane (43 percent), failure to yield right of way (22 percent), and speeding (21 percent).

Since the mid-1990s, the prevalence of marijuana detected in fatally injured drivers has increased markedly. During the same time period, 28 states and the District of Columbia have enacted legislation to decriminalize marijuana for medical use, including eight states that have further decriminalized possession of small amounts for adult recreational use. Although toxicological testing data indicate a continuing increase in marijuana use among , a positive test does not necessarily infer marijuana-induced impairment.

"While -impaired driving remains a leading cause of traffic fatalities in the United States, driving under the influence of marijuana and other drugs has become more prevalent in the past two decades," said Dr. Li, who is also the founding director of Columbia University's Center for Injury Epidemiology and Prevention. "Countermeasures targeting both drunk driving and drugged driving are needed to improve traffic safety."

Explore further: Marijuana use involved in more fatal accidents in Colorado

Related Stories

Marijuana use involved in more fatal accidents in Colorado

May 15, 2014
The proportion of marijuana-positive drivers involved in fatal motor vehicle crashes in Colorado has increased dramatically since the commercialization of medical marijuana in the middle of 2009, according to a study by University ...

Up in smoke or bottoms up: How policy could affect substance abuse

January 12, 2015
Half of young drivers who died in car crashes in American states such as California, Hawaii and West Virginia were under the influence of either alcohol or marijuana, or both. This is the story told by the statistics recording ...

Marijuana use may double the risk of accidents for drivers

October 6, 2011
Over 10 million people age 12 or older are estimated to have driven under the influence of illicit drugs in the prior year, according to a 2009 National Survey on Drug Use and Health. While marijuana is the most commonly ...

Since passing medical marijuana laws, states have seen lower numbers of fatal car crashes involving opioids

September 15, 2016
A study conducted at Columbia University's Mailman School of Public Health found that there were fewer drivers killed in car crashes who tested positive for opioids in states with medical marijuana laws than before the laws ...

Signs point to sharp rise in drugged driving fatalities

January 30, 2014
The prevalence of non-alcohol drugs detected in fatally injured drivers in the U.S. has been steadily rising and tripled from 1999 to 2010 for drivers who tested positive for marijuana—the most commonly detected non-alcohol ...

New teen drivers face triple the risk of a fatal crash

June 1, 2017
(HealthDay)—Newly minted teen drivers in the United States have almost triple the risk of being involved in a deadly crash than adults, a new study finds.

Recommended for you

Accurate measurements of sodium intake confirm relationship with mortality

June 21, 2018
Eating foods high in salt is known to contribute to high blood pressure, but does that linear relationship extend to increased risk of cardiovascular disease and death? Recent cohort studies have contested that relationship, ...

Fans of yoga therapy have yet to win over doctors

June 21, 2018
Yoga practitioners often tout the unique health benefits of the ancient discipline—from relieving stress and pain to improving vascular health—but most doctors remain sceptical in the absence of hard proof.

Fruit and vegetables linked to changes in skin colour, new research finds

June 21, 2018
Skin colour in young Caucasian men is strongly linked to high levels of fruit and vegetable consumption, new research by Curtin University has found.

What a pain: The iPad neck plagues women more

June 20, 2018
Is your iPad being a literal pain in the neck?

Medicaid work requirements and health savings accounts may impact people's coverage

June 20, 2018
Current experimental approaches in Medicaid programs—including requirements to pay premiums, contribute to health savings accounts, or to work—may lead to unintended consequences for patient coverage and access, such ...

Introduction of alcohol found to adversely impact fertility rates in hunter-gatherer community

June 19, 2018
Fernando Ramirez Rozzi, a research director with the French National Centre for Scientific Research has found that the introduction of alcohol to a Baka pygmy hunter-gatherer society caused fertility rates to fall. In his ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.