Through a grant from Ford Driving Skills for Life and GHSA, the Washington Traffic Safety Commission partnered with the Cascade Pacific Action Alliance's (CPAA's) Youth Marijuana Prevention and Education Program (YMPEP) for a campaign warning teens about the dangers of marijuana-impaired driving.
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.
- 7 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.
The Louisiana Highway Safety Commission (LHSC) was one of five State Highway Safety Offices to receive a grant from GHSA and ride hailing company Lyft to prevent impaired driving during the 2018 holiday season. With its grant, LHSC complemented its annual "Drive Sober or Get Pulled Over" enforcement campaign with social media messaging to spotlight discounted Lyft rides.
As drug-impaired driving continues to be a growing issue on our roads, Maine Bureau of Highway Safety Director and GHSA Secretary Lauren Stewart explains the challenges of assessing drivers impaired by multiple legal or illegal substances.
Story by David Charns
June 5, 2019
As more states move to legalize recreational marijuana, many are considering legalization's impact on drug-impaired driving. GHSA researcher Dr. Jim Hedlund elaborates on the available research.
Story by Mary Wisniewski
May 6, 2019
Like many states, Maine is facing a growing concern about drug-impaired driving. Maine Bureau of Highway Safety Director and GHSA Secretary Lauren Stewart addresses the challenge of poly-drug use.
Story by Marissa Bodnar
May 6, 2019
The Colorado DOT's Cannabis Conversation campaign is working to get the message out against driving under the influence of marijuana. CDOT's Sam Cole discusses the importance of the effort.
Story by Paula Haddock
April 25, 2019
To better assess drug-impaired drivers, states have begun legalizing the use of electronic warrants for roadside blood tests. This article mentions the findings of GHSA's latest report on drugged driving.
Story by Jenni Bergal
April 18, 2019
The California Office of Traffic Safety (OTS) was one of five states to receive a grant from Lyft and GHSA in 2018. With this funding, OTS augmented its "Go Safely, California" campaign during the holiday season to provide discounted Lyft rides to impaired travelers.
As Michigan prepares to implement legalized recreational marijuana, the Michigan Office of Highway and Safety Planning's annual traffic summit considered how legalization may impact traffic safety.
Story by Mikenzie Frost
March 19, 2019
As the recipient of a grant from GHSA and Lyft, the Illinois Department of Transportation (IDOT) teamed up with the Illinois State Police (ISP) for "Ride Smart," a social media campaign encouraging ride-hailing as an alternative to impaired road use.