Many Drivers In Marijuana-Legal States Drive Under the Influence

WRITTEN BY: Julia Matseikovich


As of 2022, over ten states have legalized the use of recreational marijuana. Studies have shown that in those states, 3 in 5 drivers are now driving while impaired with marijuana in their system.

Questions abound regarding this issue. Is it safe to drive using marijuana? How long should you wait before going? Have accidents increased due to drug-impaired driving?

Does marijuana stay in your system longer if you consume it rather than smoke it? Are there specific laws regarding limiting drugs in your system while driving in those states?

Different ways of using marijuana/cannabis

There are different ways of ingesting marijuana besides smoking. There are sprays, capsules, drinks, and oils used when cooking. How you ingest marijuana will depend on how long your “high” will last and how soon you can drive safely without impairment after marijuana use.

When you smoke marijuana, the cannabinoids immediately absorb through the lungs and into the bloodstream. Smoking marijuana allows tetrahydrocannabinol (THC), the psychoactive ingredient in cannabis, to quickly make it to the brain to receive the desired euphoric effect. But this also means that this feeling only lasts about one to four hours.

Edibles are food or drink items made with marijuana. The ingredients of edibles are delta-9-tetrahydrocannabinol (delta-9-THC), cannabidiol (CBD), or both. Unlike when you smoke, edibles enter the body through the digestive tract and liver.

Digesting edibles takes longer for the THC to enter the bloodstream and hit the brain. The effects of edibles can last up to twelve hours.

Driving while under the influence

There is much controversy regarding the different views of driving under the influence of alcohol compared to the effects of marijuana.

For marijuana, there is no statistically significant change in the risk of a crash associated with using that drug before driving. Alcohol use, measured at a blood alcohol concentration (BAC) threshold of 0.05 or above, will increase your odds of a wreck by seven percent.

Effects of marijuana

Marijuana use affects everyone differently. There may not be a significant increase in crash risk compared to alcohol use. Still, cannabis will slow your reaction time, impair your ability to make decisions quickly and harm your driving performance. If you can’t operate a motor vehicle, wait until the euphoria disappears.

Currently, toxicology and blood tests can detect marijuana use, but those tests can only tell you if there has been cannabis use within the past month.

Unlike the measurement of blood alcohol concentration to determine DUI, there is no way to indicate the level at which a driver using marijuana would be considered “under the influence” and have a driving impairment.

Drug-impaired accidents

Since the legalization of recreational marijuana use in the state of Washington in 2012, a traffic safety survey completed in the past year has shown that the number of drivers who test positive for marijuana after a fatal crash has doubled.

This number has increased from about 9% to around 18%, as reported by The National Highway Traffic Safety Administration (NHTSA), with the prevalence of cannabis use.

However, they also pointed out that the study found only a parallel between the legalization of cannabis and an increased number of drivers involved in fatal motor vehicle crashes that tested positive, not a resourceful link between the two.

Law enforcement and marijuana use

Under the federal law of the United States, it’s illegal to possess marijuana/cannabis. However, independent state laws vary. Multiple laws can be confusing because ten states have zero tolerance for THC.

Three states have zero tolerance for THC, but there’s no restriction on metabolites. Four states have specific per se limits for THC, and one state has a permissible law for THC. Metabolites are the product of the body breaking down and dissolving the THC.

Standard field sobriety tests such as the breathalyzer don’t apply to marijuana use. A toxicology report testing blood, urine, or saliva is typically used to determine cannabis use for impaired driving.

Zero tolerance states

Twelve states have zero-tolerance laws for THC: Arizona, Delaware, Georgia, Indiana, Iowa, Michigan, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Utah, and Wisconsin.

Per Se limit states

Five states consider you to be an impaired driver when your THC limit reaches between 2 nanograms per milliliter to 5 nanograms per milliliter of blood. They include Illinois, Montana, Nevada, Ohio, and Washington.

Colorado is unique

Colorado has what is called reasonable inference laws, and they differ from per se laws. They allow drivers charged with driving on THC an affirmative defense to show that despite having tested at or above the legal limit, their drug use did not impair their driving ability.

Colorado legalized recreational marijuana in 2012. However, the number of car crashes with fatalities in which drivers tested positive for THC increased from 18 in 2013 to 77 in 2016.

Medical Marijuana

Even though federal law says marijuana use is illegal and considered an illicit drug, all states have legalized medical marijuana except Alabama, Idaho, Nebraska, North Carolina, South Carolina, Tennessee, and Wyoming.

Georgia, Indiana, Iowa, Kentucky, and Wisconsin, have legalized the medical use of CBD oil but not THC. CBD oil does not contain the substance THC, the psychoactive ingredient that makes you “high.”

Repercussions of driving under the influence of drugs

Some states view driving under the influence of drugs the same as they do alcohol. You could receive a DUI charge, have your license suspended, serve time in jail, be required to go to drug abuse classes for substance abuse, and more, depending on your level of impairment. Your auto insurance would also be affected by the issuance of a DUI, in which you would need to get an SR-22 insurance policy.

License suspension

Driving under the influence of drugs is a severe crime and can result in suspending or revoking your driver’s license, just like driving under the influence of alcohol.

Jail time

Every state has its minimum sentences for drugged driving. Some states consider drugged driving the same as alcohol-impaired driving and have strict laws and punishments, including an extended jail stay. You could also be financially responsible for any fines applicable. These can be pretty expensive if your drugged driving results in a car crash.

Auto insurance consequences

If convicted of drugged driving, your auto insurance rates can increase between 33% and 314%, depending on your state. You would be required to obtain an SR-22 policy for auto insurance coverage at that point.


How many of these drivers are in their twenties?

Around 18% of marijuana-impaired drivers are in their twenties.

Roughly 60% of drivers who use marijuana legally have admitted to marijuana-impaired driving.

How many people are marijuana users that are driving under the influence in the United States?

According to the Centers for Disease Control and Prevention, after alcohol, marijuana is the most commonly used drug. Even though it’s illegal in most of the country, an estimated 48.2 million people used marijuana at least once in 2019.

Are marijuana users more likely to cause car accidents?

The IIHS has done studies on drivers high on marijuana; it found that they have slower reaction times, find it harder to pay attention, have difficulty staying in their lane, and make more mistakes when something goes wrong. But tests have also shown marijuana-impaired drivers are more likely to drive slower, try to pass other cars less, and tend to keep more distance between vehicles.

Is it safe to drive after smoking marijuana?

The answer to this question is difficult to answer. It will depend on the level of THC involved, how much you smoked, and how long after you smoked marijuana, you wait.

Is It Okay to Drive After Doing Marijuana?

Driving on marijuana/cannabis is a very controversial subject. Depending on your regular marijuana use and tolerance to the effects of cannabis, your driving behavior may not change. You can face extreme consequences if you live in a state where marijuana is illegal.

If you have received a DUI because your state hasn’t legalized marijuana and need assistance with your new auto insurance requirements, you can use our online tools to learn more.