What You Need to Know about Getting High and Driving in 2017

marijuana and driving

Marijuana legalization in the U.S. is constantly evolving, and states continue to modify their own legislation on their own timelines. In order for us to give you the skinny on the rules of marijuana and driving nationwide, let’s break down where some Americans can toke up today. As of January 2017:

  • 8 states plus Washington D.C. allow the recreational use of marijuana (following the 2016 election initiatives)
  • 28 states permit the medical use of marijuana
  • 20 states allow medical marijuana use for some conditions

Further, states which have passed marijuana legalization laws are some of the most populous in the union. Now, one fifth of the U.S. population lives in one of the eight states where recreational marijuana use is legal, and three-fifths of the U.S. population live in a state where medical marijuana is legal.

The Latest Marijuana Legalization Laws by State

(including updates since the November 2016 election cycle)


Medical Marijuana Legalized

Recreational Marijuana Legalized

New Hampshire
New Jersey
New Mexico
New York
North Dakota
Rhode Island
Washington, D.C.

*In Maine, adults can own and grow small amounts (up to 2.5 ounces) of marijuana. Selling and buying will eventually be legal (9 months from January 30, barring delays), but lawmakers need to make a regulatory system first. Additionally, Massachusetts lawmakers are still battling over the details of its new law.

smoking marijuana and driving

In addition to the eight states and D.C. that have legalized recreational marijuana, 13 states have decriminalized marijuana for adults, meaning if you’re found with a small amount of marijuana in your possession you’ll be either fined or charged with a misdemeanor instead of a felony. These are: 

  • Connecticut
  • Delaware
  • Illinois
  • Maryland
  • Minnesota
  • Mississippi
  • Missouri
  • New York
  • North Carolina
  • Nebraska
  • Ohio
  • Rhode Island
  • Vermont

And in addition to the 28 states that have legalized medical marijuana (which include the eight states and D.C. which have also legalized recreational use), 15 states which have not legalized medical marijuana but allow cannabinoid preparations (so, non-smokable cannabis) for certain people with certain medical conditions (like epilepsy) are:

  • Alabama
  • Georgia
  • Iowa
  • Kentucky
  • Mississippi
  • Missouri
  • North Carolina
  • Oklahoma
  • South Carolina
  • Tennessee
  • Texas
  • Utah
  • Virginia
  • Wisconsin
  • Wyoming

Only four states – Idaho, Kansas, Louisiana, and South Dakota – prohibit marijuana completely.

U.S. voters and legislatures are softening on marijuana and demonstrate their approval of responsible adults using marijuana in their homes. But particulars of the laws, including when certain provisions take effect, can be confusing. If you plan to use marijuana either medically or recreationally (and live in a state that allows such use) it’s important to keep up on how the laws are put into effect.

For instance, residents of Maine voted to legalize recreational marijuana use in November 2016, but the law didn’t go into effect until January 30, 2017, and though recreational use is allowed in Massachusetts now, lawmakers are still battling over the details of the voter-passed law, so the amount a person is allowed to have in their possession may change.

As legislation continues to change, we’ve kept an eye on how legalization (or lack thereof) impacts driving and possession laws.

Driving under the influence of a controlled substance is illegal, and pot is still a controlled substance.

Marijuana and Driving

The Law: Driving

Marijuana is still a controlled substance, and driving under the influence of controlled substances is never allowed – even in states that have legalized recreational and medical use.

If you’re pulled over or cause a crash or other traffic incident, you can be tested for drugs (either with a visual field exam by a police officer or with a blood test), you can be cited for a DUI and you might even be arrested – even if you have a medical marijuana card.

The Law: Possession

If marijuana possession is legal in your state, and you are an adult, then you are allowed to have it in your house, car, or on your person – but not necessarily in any form. Each state sets its own age limits and possession limits, and a few states (New York, Minnesota, and Pennsylvania) only allow “non-smokable cannabinoid preparations” for medical use.

marijuana and driving
Weed in your car?

…But Is Driving While High Dangerous?

The U.S. Department of Transportation released a study in February 2015 highlighting the risks of driving under the influence of alcohol and THC. They found that drivers with a BAC (blood-alcohol content) of .05% (which is still under the legal limit of .08%) have a 20% crash-risk increased as compared to sober drivers. The same study found that drivers with THC in their systems were not any more likely to crash than a sober driver (when findings were adjusted for age, gender, ethnicity, and alcohol use).

It’s important to note that no standardized way to measure a driver’s THC impairment yet exists, and states are still working out how to determine safe levels for driving.

Some folks, however, are already pointing to marijuana legalization as a factor in traffic fatality reduction. Last month The Washington Post highlighted a study by Columbia University’s Mailman School of Public Health that found, “an 11 percent reduction in traffic fatalities on average when examining places that have enacted medical-marijuana laws.” A senior author on the study theorized that people, especially younger ones, were likely substituting marijuana for alcohol in these states meaning fewer alcohol-impaired people were on the roads, reports The Washington Post.

Can Police Test You for Marijuana?

In the past, if traffic police suspected a driver of drug impairment but, they’d search the car and driver, arrest the driver for possession, get the driver off the road. But police officers can no longer arrest drivers for possession in states where marijuana use is legal (as long as the driver has less than the limit set by the state).

Police officers will assess drivers for marijuana impairment, but they often rely on field exams, which are imperfect and subjective.

Marijuana works in the body much differently than alcohol. It’s fat-soluble, meaning levels of tetrahydrocannabinol (THC) can remain in a person’s body even weeks after use. There isn’t yet a standardized way to measure a driver’s THC impairment and safe levels for driving have yet to be determined.

As we’ve written, some states, like Arizona, take a zero-tolerance approach to THC in a driver’s system, while other states, like Maine, are attempting to set legal THC levels (like legal alcohol levels) driver must abide by, but these laws are by no means standardized across the U.S. and they are subject to change.

Because marijuana can remain in your system for weeks after use, it’s possible to fight a DUI by proving the levels of drug in your system were too low to cause impairment, but the fight is expensive and time consuming.

What Should You Do If You’re Pulled Over with Weed in Your Car?

Laws about driving with cannabis vary widely state to state, but there are a few best practices from an attorney to consider if you’re transporting cannabis while driving:

  • Keep it in your trunk, glove box, or someplace else neither the driver nor passenger could access it. Store it in a sealed container. (Just as you don’t want to be caught with an open container of alcohol in your vehicle, you don’t want there to be any question about whether about not you were smoking while driving).
  • Never travel with more than your state’s limit. In Washington state, for example, each person is allowed to possess one ounce of marijuana, but in Idaho, anything more than three ounces is a felony (see each state’s possession laws here).
  • If you plan to cross state lines, remember that possession laws will be different, so make sure you’re in compliance.

The Future of Marijuana Toxicology Testing for Drivers

Though there isn’t a breathalyzer equivalent for THC yet, NPR reports that a University of Massachusetts professor, Michael Milburn, invented an iPad app called Druid that’s designed to measure marijuana intoxication, things like, “slow reaction time, misperception of time passing and inability to handle divided attention tasks.” Instead of relying on police perception, the app calculates an impairment score that, Millburn hopes, will soon be standardized.

For now, as marijuana laws across the country change at an uneven pace, if you plan to use marijuana, be responsible. Make sure you stay informed of your state’s laws (and how they might change) – especially when behind the wheel.

  • Denise Valenti

    IMMAD-Impairment Measurement Marijuana and Driving is simple table application for law enforcement. It relies on retinal dopamine depletion with marijuana. Test science is complex, but the IMMAD test is simple. Two minute test that uses very small blinky targets. If high you can not see some of the targets. It was developed for use with Alzheimer’s disease. Marijuana impairs driving worse than mild or moderate dementia does.