Drug Impaired Driving

Every state has laws dealing with alcohol-impaired driving and drug-impaired driving. But unlike the laws for alcohol-impaired driving, those that address drug-impaired 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

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 alcohol-impaired driving, those that address drug-impaired driving are nuanced, difficult to enforce and prosecute and vary substantially by state.

Marijuana tied to more Colorado collisions but not fatalities, pair of studies says

While recent research by IIHS saw a link between legalized recreational marijuana and increased crash claims, a separate study observed no significant change in traffic fatalities in states with legalized marijuana. GHSA's Kara Macek discusses the challenges of drugged driving research.

Marijuana tied to more Colorado collisions but not fatalities, pair of studies says

June 26, 2017
Article by Jack Queen

Tiger Woods’ arrest reflects nationwide surge in drugged driving

Tiger Woods' May 2017 arrest on suspicion of DUID brought national attention to the growing issue of drug-impaired driving. Dr. Jim Hedlund, author of GHSA and Responsibility.org's recent drugged driving report, discusses the issue in this article.

Tiger Woods’ arrest reflects nationwide surge in drugged driving

Article by Jorge Milian and John Pacenti
June 1, 2017

Subscribe to Drug Impaired Driving