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.
    • 8 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.
  • 6 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
Unlike the laws for drunk driving, those that address drugged driving are nuanced, difficult to enforce and prosecute and vary substantially by state.

DUID Training Grant: Vermont

Through a grant from the Foundation for Advancing Alcohol Responsibility (Responsibility.org) and GHSA, the Vermont State Highway Safety Office – Behavioral Safety Unit (SHSO - BSU) provided Advanced Roadside Impaired Driving Enforcement (ARIDE) training to law enforcement.

Vermont is experiencing an increase in drug impaired driving. Impairment by alcohol, drugs or both was a contributing factor in nearly half of Vermont’s fatal crashes in 2018, yet only a small percentage of law enforcement officers in Vermont are currently ARIDE trained.

DUID Training Grant: South Dakota

The South Dakota Office of Highway Safety (SDOHS) received a grant from GHSA and the Foundation for Advancing Alcohol Responsibility (Responsibility.org) to hold an Impaired Driving Conference in December 2019. Nearly 100 law enforcement officers attended, as well as prosecutors from South Dakota, North Dakota, Iowa and Nebraska.

DUID Training Grant: West Virginia

The West Virginia Governor’s Highway Safety Program (GHSP) used grant funding from GHSA and the National Highway Traffic Safety Administration (NHTSA) to hold a multiday training session to educate participants on different aspects of drugged driving cases and the prosecution process.

The West Virginia GHSP partnered with the West Virginia Traffic Safety Resource Prosecutor (TSRP) to organize a “West Virginia Prosecuting the Drugged Driver Course” in September 2019. Thirteen Assistant Prosecutors/Assistant Attorneys General and 12 drug recognition expert (DRE) officers attended.

DUID Training Grant: Oklahoma

The Oklahoma Highway Safety Office (OHSO) used grant funding from GHSA and the National Highway Traffic Safety Administration (NHTSA) to develop standard operating procedures (SOPs) for two oral fluid testing devices. Oklahoma’s Board of Tests for Alcohol and Drug Influence approved these devices for use but required field testing to develop proper standard procedures.

School Bus Drivers Impaired by Drugs, Alcohol Risk Lives of Hundreds of Kids

A Stateline investigation identified 38 states in which police arrested or cited school bus drivers since 2015 for allegedly driving a bus while impaired by alcohol or drugs, putting more than a thousand kids at risk.

School Bus Drivers Impaired by Drugs, Alcohol Risk Lives of Hundreds of Kids

Story by Jenni Bergal 

January 10, 2020

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