
New marijuana commercialization and legalization laws are having an impact on the safety of our public streets and highways; leaving law enforcement and courts with few tools to protect innocent lives. Currently eight states permit marijuana use for adults (both medical and nonmedical), but the laws concerning driving under the influence of marijuana are still evolving or non-existent.
Fatal crashes involving drivers who recently used marijuana doubled in Washington after the state legalized the drug. Washington was one of the first two states to legalize the recreational use of marijuana, and these findings serve as an eye-opening case study for what other states may experience with road safety after legalizing the drug.
Legal limits, also known as per se limits, for marijuana and driving are arbitrary and unsupported by science

Marijuana for non-medical use approved by voters:
*indicates the state also allows medical marijuana
Washington
2012*
Washington State (2012)
- It is not lawful to operate a motor vehicle with a level of five nanograms per milliliter of tetrahydrocannabinol (THC) in the blood, as detected by a blood draw… [READ MORE]
Colorado
2012*
Colorado (2012)
- Colorado law specifies that drivers with five nanograms of active tetrahydrocannabinol (THC) in their whole blood can be prosecuted for driving under the influence (DUI). However…[READ MORE]
Oregon
2014*
Oregon (2012)
- Driving under the influence of intoxicants (DUII) refers to operating a motor vehicle while intoxicated or drugged, including impairment from the use of marijuana… [READ MORE]
Alaska
2014*
Alaska (2014)
- Driving High on Marijuana is a DUI even though marijuana use is legal for adults in Alaska, driving while impaired is illegal and unsafe. Getting high before you drive could get you arrested for driving …[READ MORE]
California
2016*
California (2016)
- In California it illegal to drive a vehicle while under the influence of drugs including marijuana. Unlike California’s DUI of alcohol law, there is no legal limit for marijuana, or more specifically…[READ MORE]
Nevada2016*
Nevada (2016)
- In Nevada it is unlawful for any person who is under the influence of a controlled substance or under the combined influence of intoxicating liquor and a controlled substance…[READ MORE]
Maine
2016*
Maine (2016)
- Maine also uses Drug Recognition Experts (DRE) in the field to identify marijuana impaired drivers… [READ MORE]
Massachusetts
2016*
Massachusetts (2016)
- It is illegal to drive while under the influence of marijuana in Massachusetts.
- In Massachusetts if marijuana in an automobile it must be kept in the trunk or inside a locked glove compartment… [READ MORE]
District of
Columbia
District of Columbia (2014)
- A person can be arrested for operating a vehicle or boat under the influence of marijuana
- The psychoactive component of marijuana (THC) is detectable in a…[READ MORE]