Cannabis and Driving: Data and Research

Driving high is dangerous, and we want cannabis users and the general public to have the facts on the impacts of cannabis-impaired driving. There is a growing body of state data and academic research that shows cannabis does have physiological effects that impair driving – and that people are being injured and killed as a result.

State and National Data Resources on Cannabis-Impaired Driving

Bar chart showing 2019–2023 data on cannabis users who reported driving within 2–3 hours after use, ranging from 15% to 18.6%.
Driving After Using Cannabis (2019–2023): Percentage of past-30-day cannabis users who reported driving within 2–3 hours of use: 2019: 18.6%, 2020: 17.5%, 2021: 17.5%, 2022: 15.0%, 2023: 18.4%. Source: CDPHE Behavioral Risk Factor Surveillance System (BRFSS) database.

Bar chart titled "Fatalities in Crashes with Driver ≥ 5NG THC" from 2019 to 2023.
Fatalities in Crashes with Driver ≥ 5NG THC (2019-2023): Number of Colorado roadway fatalities involving drivers who tested positive for 5 nanograms per milliliter or greater of active Delta-9 THC: 2019: 56, 2020: 52, 2021: 92, 2022: 101, 2023: 87. Source: NHTSA Fatality Analysis Reporting System (FARS), Colorado Department of Public Safety.

Line graph showing a rise in polydrug involvement in fatal crashes from 24% in 2018 to 33% in 2023 in Colorado.
Polydrug Involvement in Fatal Crashes (2018–2023): Percentage of Colorado drivers in fatal crashes who tested positive for multiple impairing substances, including alcohol: 2018: 24%, 2019: 19%, 2020: 20%, 2021: 25%, 2022: 29%, 2023: 33%. Source: CDOT Data Intelligence Group, Toxicology Data (2023). Note: Includes drivers who tested positive for two or more categories of impairing substances such as alcohol, cannabinoids, stimulants, depressants, hallucinogens, narcotics, dissociative anesthetics, and inhalants.

Links to state and federal impaired driving data resources

Links to Academic Research on Cannabis and Driving Impairment

There are many misconceptions about marijuana use, including rumors that it can’t impair your ability to drive or that it can actually make you a safer driver. Several scientific studies indicate that this is false. Research shows that marijuana impairs motor skills, reaction time, lane tracking and cognitive functions.