Science on Cannabis
Impaired Driving, Traffic Fatality Risk
To learn about what scientists are discovering about cannabis and the risk of traffic fatalities, click on the titles of the research studies below.
Researchers say nationwide marijuana legalization will add 6800 traffic fatalities annually.
U.S. Research Studies
Use of Alcohol and Cannabis Among Adults Driving Children in Washington State
Romano 2019: Romano, E., Kelley-Baker, T, Eichelberger, A., Ramirez, A.
–Journal of Studies of Alcohol and Drugs
Recreational Cannabis Use Impairs Driving Performance in the Absence of Acute Intoxication
Dahlgren 2020: Dahlgren, K., Sagar, K.A., Smith, R.T., Lambros, A.M., Kuppe, M.K., Gruber, S.A.
–Drug and Alcohol Dependence
The Effect of Cannabis Compared with Alcohol on Driving
Sewell 2009: Sewell, A., Poling, J., Sofuoglu, M.
–American Journal on Addictions
Effects of Chronic Marijuana Use on Driving Performance
Doroudgar 2018: Doroudgar, S., Chuang, H.M., Bohnert, K., Canedo, J., Burrowes, S., Perry, P.J.
–Traffic Injury Prevention
Cannabis effects on driving lateral control with and without alcohol
Hartman 2015: Hartman, R.L., Brown, T.L., Milavetz, G., Spurgin, A., Pierce, R.S., Gorelick, D.A., Gaffney, G., Huestis, M.A.
–Drug and Alcohol Dependence
Cannabis Effects on Driving Skills
Hartman 2013: Hartman, R.L., Huestis, M.A.
–Clinical Chemistry, March 2013
Fatal crashes in the 5 years after recreational marijuana legalization in Colorado and Washington
Aydelotte 2019: Aydelotte JD, Mardock AL, Mancheski CA et al.
–Accident Analysis & Prevention
The April 20 Cannabis Celebration and Fatal Traffic Crashes in the U.S.
Staples 2018: Staples, J.A., Redelmeier, D.A.
–JAMA Internal Medicine, April 2018
Drug Recognition Expert (DRE) examination characteristics of cannabis impairment
Hartman 2016: Hartman, R.L., Richman, J.E., Hayes, C.E., Huestis, M.A.
–Accident Analysis and Prevention
Marijuana and DUI Fatal Crashes Differ
by Time of Day & Day of Week
Crancer 2017: Alfred Crancer, B.S., M.A., Phillip Drum, Pharm. D.
Delays in DUI Blood Testing: Impact on Cannabis DUI Assessments
Wood 2015: Ed Wood, Ashley Brooks-Russell, Phillip Drum, Pharm. D.
The Relative Risk of Motor Vehicle Collision on Cannabis Celebration Day in
–Accident Analysis and Prevention, July 2019
International approaches to driving under the influence of cannabis: A review of evidence on impact
–Drug and Alcohol Dependence, December 2016
Psychomotor Function in Chronic Daily Cannabis Smokers during Sustained Abstinence
Bosker 2013: Bosker WM, Karschner EL, Lee D, Goodwin RS, Hirvonen J, et al.
Cannabis and tolerance: acute drug impairment as a function of cannabis use history
Ramaekers 2016: Ramaekers JG, van Wel JH, Spronk DB.
Monitoring Health Concerns Related to Marijuana in Colorado: 2016
See Marijuana Use and Driving section pg 145-156
Driving Under the Influence of Drugs and Alcohol
A Report Pursuant to U.S. House Bill 17-1315
Position on Cannabis (Marijuana) and Driving
2017, NSC Alcohol, Drugs and Impairment Division
–National Safety Council
Drug-Impaired Driving: Marijuana and Opioids Raise Critical Issues for States
–Governors Highway Safety Administration
Marijuana Use, Alcohol Use, and Driving in Washington State
Grondel 2018: Grondel D, Hoff S, Doane D.
–Washington State Traffic Safety Commission