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.

Ford DSFL Teen Driving Grant Results: Colorado

The Eagle County, Colorado Prevention Committee received special funding from Ford Driving Skills for Life to tackle the issue of drug-impaired driving among teens in their community. With this grant, the Committee was able to host a number of events and activities for teens throughout the year, including booths at concerts, a youth safe driving fair, and a "Safe and Sober Glow Party."

'Drugged driving' surpasses drunken driving among drivers killed in crashes, report finds

As drug-impaired driving becomes a growing issue, GHSA's recent report provides updates on the newest research and programs combating this challenge. Report author Dr. Jim Hedlund explains the report's findings and greatest concerns.

'Drugged driving' surpasses drunken driving among drivers killed in crashes, report finds

April 28, 2017
Article by Robert Jimison

In Two Years, Drugged Driving Deaths Rose While Drunk Driving Deaths Fell

Though fewer fatally injured drivers are testing positive for alcohol, more are being found with drugs in their system. Dr. Jim Hedlund, author of GHSA's latest report on drug-impaired driving, speaks with Forbes on the report's findings.

In Two Years, Drugged Driving Deaths Rose While Drunk Driving Deaths Fell

April 26, 2017
Article by Cheryl and Christopher Jensen

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

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