Drug Impaired Driving

Every state has laws dealing with alcohol-impaired driving and drug-impaired driving. But unlike the laws for drunk driving, those that address drugged driving are nuanced, difficult to enforce and prosecute and vary substantially by state.

In addition to general impairment laws, there are two basic laws that states tend to use when addressing drug-impaired driving:

  • Zero Tolerance laws make it illegal to drive with any measurable amount of specified drugs in the body. These laws are best suited for illegal drugs: if it is illegal to possess or use a drug, then it is reasonable to prohibit driving after the drug has been possessed and used.
    • 16 states have zero tolerance laws in effect for one or more drugs.
  • Per Se laws make it illegal to drive with amounts of specified drugs in the body that exceed set limits.
    • 6 states have per se laws in effect for one or more drugs.

Marijuana Drug-Impaired Driving Laws

18 states have zero tolerance or non-zero per se laws for marijuana.

  • 9 states have zero tolerance for THC or a metabolite.
  • 3 states have zero tolerance for THC but no restriction on metabolites.
  • 5 states have specific per se limits for THC
  • 1 state (Colorado) has a reasonable inference law for THC

A PDF list of state marijuana-related laws is also available here.

NOTE: GHSA does not compile any additional data on drug impaired driving laws other than what is presented here. For more information, consult the appropriate State Highway Safety Office.

Sources: State Highway Safety Offices.

Short Term Description
Every state has laws dealing with alcohol-impaired driving and drug-impaired driving. But unlike the laws for drunk driving, those that address drugged driving are nuanced, difficult to enforce and prosecute and vary substantially by state.

Drug use tops booze for first time in fatal U.S. crashes: study

GHSA's updated report on drug-impaired driving sees that 43% of fatally-injured drivers with known test results tested positive for drugs, more than the presence of alcohol. Dr. Jim Hedlund, author of the report, talks with Reuters about what this finding means.

Drug use tops booze for first time in fatal U.S. crashes: study

April 26, 2017
Article by Ian Simpson

More police training, public education needed to stop 'drugged' driving: report

GHSA's recent update to its report Drug-Impaired Driving: A Guide for States looks at the latest research, data and programs addressing this issue. Report author Dr. Jim Hedlund discusses the report's findings.

More police training, public education needed to stop 'drugged' driving: report

April 26, 2017
Article by Mary Wisniewski

Responsibility.org Drugged Driving Grant Results: Florida

Florida State Safety Office

The Florida Department of Transportation State Safety Office was a recipient of GHSA and Responsibility.org’s 2016 grant program aimed at training law enforcement in drug recognition. Prior to receiving this grant, the Florida Highway Patrol had 11 certified Drug Recognition Experts (DREs), out of 1,869 total troopers. Faced with a high likelihood of marijuana legalization in the state and the subsequent potential for an increase in drug-impaired driving, FHP was able to train 27 additional DREs in 2016.

Shaq: Identifying Drugged Drivers ‘Difficult’ and ‘Costly’


Coverage of Responsibility.org's November 30th event, in which NBA Hall of Famer Shaquille O'Neal announced another two years of partnership between GHSA and Responsibility.org which will provide states with grants to address drugged driving through law enforcement. Article features quotes by GHSA Secretary Darrin Grondel, Director of Washington Traffic Safety Commission and winner of a Quinlan Excellence in Traffic Safety Award.

Foundation for Advancing Alcohol Responsibility

GHSA works with the Foundation for Advancing Alcohol Responsibility (Responsibility.org) to combat the growing issue of drugged driving. As drug-impaired drivers continue to be a nationwide problem, GHSA and Responsibility.org aim to ensure that law enforcement agencies and highway safety offices have all the tools available to them to identify and arrest these drivers. By putting more Drug Recognition Experts (DREs) on the road, states are better able to ensure drugged drivers are off of them.

Drug Impaired Driving

Drug-impaired driving is a growing problem in the U.S., and the laws are complex and vary by state. There are over 400 drugs that are tracked by NHTSA that can cause impairment, and each one has a different impact on every user. As states address the issue of drugged driving, the need for additional data is important.

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