Close up on a car crashed with fireman in background

New study highlights role of drug and alcohol use in serious crashes

UC Davis Medical Center is one of seven Level 1 trauma centers across the country to participate in the study


Each year, many people look forward to ringing in the new year with family and friends. However, some celebrations include the combination of alcohol and late-night driving – which can lead to fatal accidents.

According to Mothers Against Drunk Driving (MADD), between 2008 and 2012, January 1st had the highest percentage of alcohol-related vehicle deaths when compared to other days and holidays.

James Chenoweth
James Chenoweth, director of toxicology research and associate professor of Emergency Medicine

To raise awareness on the dangers of driving while impaired by alcohol or drugs, the U.S. Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) released the findings of a new study on drug and alcohol use by road users involved in serious and fatal crashes.

The study takes a closer look at the role of alcohol and drug use in serious and fatal crashes. Seven Level 1 trauma centers across the country participated in the study, including UC Davis Medical Center. Each trauma center examined blood results from large numbers of drivers, bicyclists and pedestrians involved in serious and fatal crashes. The samples were evaluated for alcohol and drugs, including legal, prescription and illegal drugs.

“Too often we see the negative effects drugs and alcohol have on roadway safety,” said James Chenoweth, director of toxicology research and associate professor of Emergency Medicine, who was a co-investigator for the study. “We are proud to have participated in the NHTSA's study because it highlights UC Davis's commitment to public safety research and the role substance use plays in motor vehicle accidents.”

The study found:

  • 56% of seriously or fatally injured road users tested positive for alcohol, or some type of drug known to have potentially impairing effects.
  • The presence of cannabinoids, such as the substances found in marijuana (25%), and alcohol (23%) were most prevalent, followed by stimulants (11%) and opioids (9%).
  • The presence of two or more drugs was reported in 18% of cases with serious injuries and 32% of the fatalities.

“The study shows a higher drug and alcohol prevalence in crashes where a driver is killed,” explained Chenoweth. “To prevent unnecessary tragedies, we urge everyone to plan ahead, especially when celebrating the holidays. Avoid crashes by always driving sober, designating a sober driver, using public transportation or calling a taxi or ride-hailing service to make sure that everyone gets home safely.”