Pot Plus Alcohol Raises Fatal Traffic Accident Risk Over 500%

MedicalResearch.com Interview with:

Guohua Li DrPH, MD Professor and Director Center for Injury Epidemiology and Prevention Department of Epidemiology Mailman School of Public Health Columbia University

Dr. Li

Guohua Li DrPH, MD
Professor and Director
Center for Injury Epidemiology and Prevention
Department of Epidemiology
Mailman School of Public Health
Columbia University

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Drugged driving has become a serious problem in the United States in the recent years due to increased consumption of marijuana and opioids. About 20% of fatally injured drivers used two or more substances, with alcohol-marijuana being the most commonly detected polydrug combination.

Our study of over 14000 fatal 2-car crashes indicates that drivers testing positive for alcohol, marijuana, or both are significantly more likely to be responsible for initiating these crashes than those using neither of the substances. Specifically, compared to drivers not using alcohol and marijuana, the risk of being responsible for initiating fatal crashes increases 62% for those testing positive for marijuana and negative for alcohol, 437% for those testing positive for alcohol and negative for marijuana, and 539% for those testing positive for both alcohol and marijuana. These results suggest that when used in combination, alcohol and marijuana have a positive interaction on the risk of fatal crash initiation.

The most common driver error leading to fatal 2-car crashes is failure to keep in proper lane, followed by failure to yield right of way and speeding.

MedicalResearch.com: What should readers take away from your report?

Response: Don’t drive after drinking alcohol or smoking pot because it is illegal and dangerous. Mixing driving with booze and pot could be deadly.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: Future research needs to determine the dose-response effect of THC on crash risk, develop reliable and noninvasive methods for measuring blood THC level and drug-induced impairment, monitor use of alcohol and drugs in the general driver population and those involved in motor vehicle crashes, and evaluate intervention programs to reduce impaired driving and crash injuries and fatalities.

MedicalResearch.com: Is there anything else you would like to add?

Response: Traffic injury remains to be a leading cause of death for adolescents and young adults. Alcohol and drugs are attributed to over 50% of traffic fatalities.

Following steady improvement in traffic safety in the 1990s and 2000s, death rates from motor vehicle crashes have reversed the long-term downward trend in the United States and increased over 10% in the past three years.

There is an urgent need to implement effective programs to control the drugged driving epidemic and reduce injury morbidity and mortality from motor vehicle crashes.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.


Guohua Li, Stanford Chihuri, Joanne E. Brady. Role of alcohol and marijuana use in the initiation of fatal two-vehicle crashes. Annals of Epidemiology, 2017; 27 (5): 342 DOI: 10.1016/j.annepidem.2017.05.003

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

More Medical Research Interviews on MedicalResearch.com

Last Updated on June 13, 2017 by Marie Benz MD FAAD