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Last updated: January 30, 2024

Driving While High on Marijuana

DUIs can involve drugs like marijuana — not just alcohol.

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In all but three states, marijuana usage is legal in some form, be it for regulated medical use or recreational. But even in states where using marijuana is 100 percent legal for adults, driving while impaired by marijuana is still illegal everywhere. That said, some states allow people to drive if they have low levels of tetrahydrocannabinol (THC) detected in their bodies, but are not “impaired,” while other states have a zero-tolerance law.

Keep reading to learn about your state’s laws surrounding marijuana usage and driving, as well as the effects that smoking, vaping or ingesting marijuana can have when you get behind the wheel.

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Laws About Driving While High on Marijuana

graphic of a person driving a car with a marijuana leaf and a large fine ticket behind them

State laws surrounding marijuana usage and driving fall into one of four categories, according to the National Conference of State Legislatures:

  • Zero tolerance: It is illegal to drive with any amount of THC or metabolites in your body.
  • Per se law: You cannot drive with amounts of THC above the legal limit, which varies by state.
  • Under the influence DUID: You cannot drive while under the influence or affected by THC, although there’s no exact threshold for impairment.
  • Permissible inference law: A driver is considered “under the influence” of marijuana if the amount of THC in their blood is 5 ng/ml or higher.1

NOTE

THC is the major psychoactive component in cannabis. The Federal Drug Administration classifies THC as a Schedule 1 drug.2

Laws and Penalties by State

See below for your state’s impaired driving law, as well as penalties for first offenses of driving while impaired from using marijuana, a specific type of DUI.

State Law governing driving after using marijuana Penalties for the first offense
Alabama Under the influence DUID Imprisonment for up to 1 year and/or

fine between $600 to $2,100

License suspension: 90 days

Ignition interlock device required for 6 months following reinstatement or 2 years if there was a child under the age of 14 in the vehicle

Alaska Under the influence DUID Jail/monitoring time: 72 consecutive hours

Fine: $1,500

Ignition interlock device: 6 months

Cost of imprisonment for offenses after 7/9/19: $330

License revocation: 90 days

Arizona Zero tolerance law Jail: 10 consecutive days maximum

Fine: $1,250 minimum

Required drug education/treatment

Must have ignition interlock device

Must perform community service

Arkansas Under the influence DUID License suspension: 6 months

Must complete a drug treatment or education program, victim impact panel class

Reinstatement fee: $150

California Under the influence DUID Suspended or revoked license

Must complete a DUI program, file an SR-22, pay license reissue/restriction fees and install an ignition interlock device

Imprisonment: Up to 6 months

Fine: Amount not specified

Impoundment: Possible and may include storage fee

Colorado Permissible inference law; driver is considered under the influence if their THC levels are 9 ng/ml or higher, but drivers can introduce an affirmative defense arguing they were not impaired DUI (driving under the influence): 5 days to 1 year in jail, fine between $600 to $1,500 or both

DWAI (driving while ability impaired): 2 days to 1 year in jail, fine between $200 to $1,500 or both

Connecticut Under the influence DUID License suspension: 45 days

Ignition interlock device: 1 year following restoration

Delaware Under the influence DUID $500 to $1,500 fine and/or 1 year of imprisonment maximum
Florida Under the influence DUID Fine: $500 to $1,000

Imprisonment: 6 months maximum

Impoundment of vehicle: 10 days, unless the family of the defendant has no other transportation

License revocation: 180 days to 1 year if no bodily injury, minimum 3 years if bodily injury

Must complete DUI school

Georgia Zero tolerance law Fine: $300 to $1,000

Imprisonment: 10 days to 12 months, plus probation

Community service: 40 hours maximum

Completion of a Drug Use Risk Reduction Program

Hawaii Under the influence DUID Substance abuse rehabilitation program: 14 hours minimum

License revocation: 1 year to 18 months

Ignition interlock device

One of the following:

Community service: 72 hours

Imprisonment: 2 to 5 days

Fine: $250 to $1,000

Surcharge: $25, either to the neurotrauma special fund or trauma system special fund

Idaho Under the influence DUID Jail: 6 months maximum

Fine: $1,000 maximum

License suspension: 30 days required, plus anywhere from 15 to 60 days but can have restricted driving privileges during this time

Ignition interlock device: 1 year following license reinstatement

Illinois Per se law; limit is either 5 ng/mg for THC or 10 ng/mg for delta-9 THC Community service: 100 hours minimum

Fine: $500 minimum

Indiana Zero tolerance law Court costs and fees: Must pay anything over $300

Jail: 1 year maximum

Fine: $5,000 maximum

License suspension: Up to 2 years or probation and required to enroll in a substance abuse education course and license suspension for 30 days, then a 180-day probation (can only drive for work purposes)

Victim impact panel, urine drug testing; other terms of probation may be required

Iowa Zero tolerance law Imprisonment: 2 days to 1 year, less any time spent in a drug program with law enforcement security

Fine: $1,250 but can waive up to $625 of fine if there was no personal or property injury

Community service: May be required

License revocation: 180 days to 1 year

Ignition interlock device: During restricted license

Substance abuse evaluation and treatment required

Kansas Under the influence DUID 1 year maximum of imprisonment, $100 to $500 fine or both
Kentucky Under the influence DUID Substance abuse program: 90 days

License suspension: 6 months but can be reduced to 4 months with an ignition interlock device for 90 days

Louisiana Under the influence DUID Imprisonment: 10 days mandatory, up to 6 months

Fine: $3,000 to $1,000

May require probation, community service and participation in a substance abuse/driver improvement program instead of mandatory sentence

License suspension: 90 days

Maine Under the influence DUID Fine: $500 minimum, or, if a person didn’t submit an alcohol test, $600 minimum

License suspension: 150 days

Imprisonment: At least 2 days or at least 4 days if person failed to submit to the test

Maryland Under the influence DUID 2 months maximum imprisonment; fine of less than $500 or both
Massachusetts Under the influence DUID Fine of $500 to $5,000, imprisonment of less than 2.5 years or both

$300 total in assessment fees

Michigan Zero tolerance law Fine: $500 maximum

Imprisonment: 93 days maximum

Community service: 360 hours maximum

License suspension: 180 days maximum

Points on driver’s license: 6

Minnesota Under the influence DUID 90 days maximum of imprisonment, $1,000 fine or both

Driver’s license revocation for 3 months to 6 years

May also lose license plate/car

Mississippi Under the influence DUID Fine of $250 to $1,000, imprisonment of 2 days maximum or both

May replace imprisonment with a victim impact panel

Driver’s license suspension: 90 days minimum but can get a restricted license for work/school/medical care after 30 days from the suspension effective date

Missouri Under the influence DUID License suspension: 90 days but may be eligible for restricted license the entire time or for 60 days

Imprisonment: 6 months maximum

Fine: $500 maximum

Montana Under the influence DUID Imprisonment: 2 days to 6 months

Fine: $600 to $1,000

If there was 1 or more passenger under 16 years old:

Imprisonment: 2 days to 1 year

Fine: $1,200 to $2,000

Nebraska Under the influence DUID License revocation: 6 months

Ignition interlock required until end of probation

Fine: $500

Nevada Per se law; felony violations at 2 ng/ml for THC and 5 ng/mg for THC metabolite Imprisonment: 2 days to 6 months

Fine: $400 to $1,000, plus $121 reinstatement fee, $35 victims compensation civil penalty, $42.25 driver’s license fee, $26 testing fee

Chemical test fee: $60

Substance abuse treatment

Victim impact panel

Must use ignition interlock device upon license reinstatement

Must pass driver’s license test

SR-22: 3 years

New Hampshire Under the influence DUID Impaired Driver Care Management Program (IDCMP): Must complete intake/screening. If screening is negative, will have to take an Impaired Driver Education Program (IDEP) or a Weekend Impaired Driver Education Program (WIDEP) and will need a complete substance use disorder evaluation within 30 days of conviction

If screening is positive, IDCMP will create a service plan If someone doesn’t comply, their license and driving privileges will be revoked until they comply

Fine: $500 minimum

Driver’s license revocation: 9 months to 2 years

New Jersey Under the influence DUID Fine: $300 to $500

Imprisonment: 30 days maximum

Driver’s license revocation or suspension: 7 months to 1 year

Other fines: $225

May require participation in a supervised visitation program as either a condition of probation or a form of community service

New Mexico Under the influence DUID Imprisonment: 90 days maximum, fine of $999 maximum or both

Probation: 90 days to 1 year

Community service: 24 hours minimum

Fine: $300

Must complete a screening program/driver drug rehabilitation program

New York Under the influence DUID Fine: $500 to $1,000

Imprisonment: 1 year maximum

License revocation: 6 months minimum

North Carolina Under the influence DUID License revocation: 1 year
North Dakota Under the influence DUID Fine: $500 to $750

Imprisonment: 2 days

License suspension: 91 to 180 days

Additional evaluation required

Ohio Per se law; cannot have more than 25 ng/ml of delta-9 THC in urine or at least 5 ng/ml in whole blood Imprisonment: 3 days mandatory, 6 months maximum

Fine: $375 mandatory, $1,075 maximum

Court may order house arrest, clinical assessment, participation in a drug education/treatment program, work release, community service, probation or more.

License suspension: 30 days

Oklahoma Zero tolerance law Imprisonment: 10 days to 1 year

Fine: $1,000 maximum

Required to have a drug assessment/evaluation and comply with all recommendations made

Oregon Under the influence DUID Fine: $1,000 minimum, plus conviction fee of $255
Pennsylvania Zero tolerance law License suspension: 1 year

Imprisonment: 3 days to 6 months

Fine: $1,000 to $5,000

Must attend alcohol safety school and treatment if ordered

Rhode Island Under the influence DUID Fine: $100 to $300

Public community restitution: 10 to 60 hours and/or imprisonment of up to 1 year

License suspension: 30 to 180 days

May be required to attend a course on driving while intoxicated

Ignition interlock may be required

South Carolina Under the influence DUID Fine: $400

Imprisonment: 2 to 30 days or 48 hours of public service employment

South Dakota Zero tolerance law License revocation: 30 days to 1 year, except for employment, 24/7 sobriety testing, attendance at school, child care delivery or pickup or attendance at counseling programs
Tennessee Under the influence DUID Fine: $350 to $1,500

Imprisonment: 2 days to 11 months

License revocation: 1 year but can have restricted license

Mandatory participation in a drug treatment program

Ignition interlock device required

Texas Under the influence DUID Fine: $2,000 maximum

Imprisonment: Mandatory 3 days, 180 days maximum

Driver’s license revocation: 1 year maximum

Utah Zero tolerance law Imprisonment: 364 days maximum

Fine: $25,000 maximum

Vermont Under the influence DUID Imprisonment: 2 years maximum

Fine: $750 maximum

May be required to participate in community service, drug education/treatment program, victim restitution or more

License suspension: 90 days mandatory

Virginia Under the influence DUID License suspension: 1 year
Washington Per se law; cannot have a THC concentration of 5 ng/mg or higher within 2 hours of driving Imprisonment: 1 year maximum

Fine: $5,000 maximum

Court may require community service, victim restitution, victim compensation fund, house arrest or more

Washington D.C. Under the influence DUID $1,000 fine, 180-day maximum imprisonment or both
West Virginia Under the influence DUID Imprisonment: 6 months maximum

Fine: $100 to $500

Wisconsin Zero tolerance law Fine: $150 to $300

License revocation: 6 to 9 months

Wyoming Under the influence DUID 6 months maximum imprisonment, $750 maximum fine or both

Must receive and pay for substance abuse assessment

How Impairment Is Measured

THC concentrations are measured in blood and urine tests. Some states, such as Alabama, are piloting oral fluid testing — which consists of testing saliva for its THC content.3

Alcohol vs. Marijuana-Impaired Driving

While driving under the influence of alcohol has proven consistently to be dangerous, the results of driving under the influence of marijuana are not as clear-cut. A person’s tolerance, smoking technique and absorption of THC cause a variety of effects that aren’t as uniform as the consequences of drinking alcohol.

However, according to the National Library of Medicine, marijuana causes more detriment to automatic driving functions, whereas alcohol affects more complex tasks. While people high on marijuana can compensate effectively, combining alcohol and marijuana makes driving safely dangerous and difficult. Still, as the organizations and studies cited below suggest, it’s not clear if marijuana usage on its own causes more accidents, even though alcohol does.

How Cannabis Impairs Driving: Is It Safe to Drive High?

Does marijuana affect your ability to drive? While this may sound like a silly question with an obvious answer, science isn’t so sure about the dangers of driving while high. Cannabis users, read this before you get into your motor vehicle after lighting up.

Historically, national institutions like the Centers for Disease Control and Prevention have found that driving while high impairs coordination, distorts perception and makes short-term memory and problem-solving difficult. This leads to more car crashes4. The National Institute on Drug Abuse (NIDA) seconds this data.

However, a recent study from the Canadian Institute of Actuaries and the Casualty Actuarial Society analyzed both Canadian and United States data about collision or private vehicle losses in fatal accidents from 2016 to 2019. While they found that marijuana impacts driving behavior, it didn’t necessarily increase risk. In some cases, marijuana usage led people to drive slower and have longer following distances.5

Another study from the National Institute of Justice and RTI International found little correlation between THC levels and impaired driving. It concluded that THC levels don’t indicate marijuana ingestion reliably. While field tests for alcohol measure impairment, marijuana intoxication isn’t so easily measured.6

Signs of Marijuana Impairment While Driving

According to the NIDA, the following driving behaviors are signs of marijuana impairment.

  • More lane weaving
  • Slow reaction time
  • Less attention to the road7

But due to conflicting study results, more research is needed to determine the relationship between THC levels and impaired driving.

Impaired Driving Statistics

Unfortunately, the statistics available on marijuana impairment while driving are lacking. The most recent data is from 2018, already five years old at the time of this writing. Still, we have some insight into how often people ingest marijuana before getting behind the wheel.

An analysis of National Highway Traffic Safety Administration’s Fatality Analysis Reporting System (FARS) data by the Governors’ Highway Safety Administration reveals the number of people killed in car accidents who were under the influence of alcohol or drugs.

Percentage of fatally injured drivers by known test results 2006 FARS Final File 2015 FARS Final File 2015 FARS Annual Report 2016 FARS Annual Report
Alcohol 41% 28% 38% 38%
Drug 28% 43% 43% 44%

The difference between the FARS Final Files and Annual Reports is that the Annual Reports may have outside variable data, which may lead to data differences in the final counts. These revisions are typically minor, however.8

But keep in mind that the category of drugs here doesn’t only refer to marijuana but also opioids, hallucinogens and other illegal drugs.

That said, when comparing marijuana usage to opioids, more people killed in car crashes in 2016 tested positive for marijuana only (38 percent) than opioids. However, 42 percent tested positive for another drug besides marijuana or opioids, which could refer to a wide range of substances.9

percentage of drug positive fatally injured drivers graph

CDC data shows that, as of 2018, 64 percent of those who reported driving under the influence of marijuana were male while only 36 percent were female. For drugs other than marijuana, such as cocaine, heroin, inhalants, hallucinogens and methamphetamines, the gender difference was even more stark.

graph of people ages 16 and older who reported driving under the influence by gender

DID YOU KNOW?

In general, men pay more for car insurance due to their higher chance of driving under the influence and getting into accidents, resulting in costly claims.

The majority of people who reported driving under the influence of marijuana (66 percent) were white, followed by Black and Hispanic people (tied for second at 13 percent). White people also were most likely to drive while under the influence of other drugs at 70 percent, compared to only 16 percent of Hispanic people and 8 percent of Black people.

graph of number of people ages 16 and older who reported driving under the influence by race

Safety Tips: How to Prevent Impaired Driving

It’s easy to prevent impaired driving: Don’t drive while impaired, even if you think you can. Let’s break this down:

  1. Don’t drive after any marijuana use.
  2. Don’t let your friends and family drive after any marijuana use.
  3. Instead, use a designated sober driver.
  4. Alternatively, use a rideshare service or public transportation to get to your destination.

Conclusion

While it’s not conclusive what effects marijuana usage has on driving behaviors, it’s best not to drive high — for safety reasons and because every state has laws against it. Instead, always get behind the wheel sober and focused, making sure you have the energy and focus you need to drive defensively.

Aliza Vigderman
Written by:Aliza Vigderman
Senior Writer & Editor
A seasoned journalist and content strategist with over 10 years of editorial experience in digital media, Aliza Vigderman has written and edited hundreds of articles on the site, covering everything from plan coverages to discounts to state laws. Previously, she was a senior editor and industry analyst at the home and digital security website Security.org, previously called Security Baron. She has also contributed to The Huffington Post, SquareFoot, and Degreed. Aliza studied journalism at Brandeis University.

Citations

  1. Drugged Driving | Marijuana-Impaired Driving. NCSL. (2022, Nov 11).
    https://www.ncsl.org/transportation/drugged-driving-marijuana-impaired-driving

  2. Tetrahydrocannabinol (THC). National Library of Medicine. (2023, May 2).
    https://www.ncbi.nlm.nih.gov/books/NBK563174/

  3. Oral Fluid Drug Testing Program. ADFS. (2023).
    https://adfs.alabama.gov/services/tox/toxicology-oral-testing-program

  4. Marijuana and Driving: How to Keep Your Fleet’s Drivers Safe. CDC. (2021, Nov 23).
    https://www.cdc.gov/niosh/newsroom/feature/marijuana-and-driving.html

  5. Assessing the Impact of Marijuana Decriminalization on Vehicle Accident Experience. Casualty Actuarial Society. (2022, Dec).
    https://www.casact.org/sites/default/files/2022-12/Marijuana-Decriminalization_Report.pdf

  6. Field Sobriety Tests and THC Levels Unreliable Indicators of Marijuana Intoxication. NIJ. (2021, Apr 5).
    https://nij.ojp.gov/topics/articles/field-sobriety-tests-and-thc-levels-unreliable-indicators-marijuana-intoxication

  7. Drugged Driving DrugFacts. NIH. (2021, Apr 5).
    https://nida.nih.gov/publications/drugfacts/drugged-driving

  8. Traffic Safety Facts Annual Report Tables. NHTSA. (2022, Jun 24).
    https://cdan.nhtsa.gov/tsftables/tsfar.htm

  9. Drug-Impaired Driving: Marijuana and Opioids Raise Critical Issues for States. GHSA. (2023).
    https://www.ghsa.org/resources/DUID18