Transparent
State Laws & FundingNewsMeetingsIssuesPublicationsResources & ProgramsAbout UsMembers Only
State Laws & Funding



Calendar Icon Highway Safety Calendar

Email Newsletter icon, E-mail Newsletter icon, Email List icon, E-mail List icon Sign Up for GHSA News

Close up of pills

Drug-Impaired Driving Laws

Every state has laws dealing with alcohol-impaired driving and drug-impaired driving. But unlike the laws for alcohol-impaired driving, those that address drug-impaired 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:

Marijuana Drug-Impaired Driving Laws

18 states have zero tolerance or non-zero per se laws for marijuana.

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.

State DUID Zero Tolerance or Per se Laws for Some Drugs
Marijuana-Specific
Possession & Use Laws
Impaired Driving Laws
Alabama None Illegal None
Alaska None Decriminalized and legal for recreational and medicinal use None
Arizona Zero tolerance for some drugs Legal for medical use Zero tolerance for THC and metabolites
Arkansas None Illegal None
California None Decriminalized and legal for medical use None
Colorado Reasonable inference law w/ legal limit >0 for THC Decriminalized and legal for recreational and medical use Reasonable inference for THC (5 ng)
Connecticut None Decriminalized and legal for medical use None
Delaware Zero tolerance for some drugs Decriminalized and legal for medical use Zero tolerance for THC and metabolites
D.C. None Decriminalized and legal for recreational and medical use None
Florida None Illegal None
Georgia Zero tolerance for some drugs Illegal Zero tolerance for THC and metabolites
Hawaii None Legal for medical use None
Idaho None Illegal None
Illinois Zero tolerance for some drugs Legal for medical use Zero tolerance for THC and metabolites
Indiana Zero tolerance for some drugs Illegal Zero tolerance for THC and metabolites
Iowa Zero tolerance for some drugs Illegal Zero tolerance for THC
Kansas None Illegal None
Kentucky Zero tolerance for some drugs Illegal None
Louisiana None Illegal None
Maine None Decriminalized and legal for medical use None
Maryland None Decriminalized and legal for medical use None
Massachusetts None Decriminalized and legal for medical use None
Michigan Zero tolerance for some drugs Legal for medical use Zero tolerance for THC
Minnesota Zero tolerance for some drugs Decriminalized and legal for medical use None
Mississippi None Decriminalized None
Missouri None Decriminalized None
Montana Per se >0 for some drugs Legal for medical use THC per se (5 ng)
Nebraska None Decriminalized None
Nevada Per se >0 for some drugs Decriminalized and legal for medical use THC per se (2 ng)
New Hampshire None Legal for medical use None
New Jersey

None Legal for medical use None
New Mexico None Legal for medical use None
New York None Decriminalized and legal for medical use None
North Carolina Zero tolerance for some drugs Decriminalized None
North Dakota None Illegal None
Ohio Per se >0 for some drugs Decriminalized THC per se (2 ng)
Oklahoma Zero tolerance for some drugs Illiegal Zero tolerance for THC and metabolites
Oregon None Decriminalized and legal for recreational and medical use None
Pennsylvania Zero tolerance for some drugs Illegal THC per se (1 ng)
Rhode Island Zero tolerance for some drugs Decriminalized and legal for medical use Zero tolerance for THC and metabolites
South Carolina None Illegal None
South Dakota Zero tolerance for some drugs Illegal Zero tolerance for THC and metabolites
Tennessee None Illegal None
Texas None Illegal None
Utah Zero tolerance for some drugs Illegal Zero tolerance for THC and metabolites
Vermont None Decriminalized and legal for medical use None
Virginia Per se >0 for some drugs Illegal None
Washington Per se >0 for some drugs Decriminalized and legal for recreational and medical use THC per se (5 ng)
West Virginia None Illegal None
Wisconsin Zero tolerance for some drugs Illegal Zero tolerance for THC
Wyoming None Illegal None
Total States Law (# of States)
Zero tolerance (16)
Per se >0 (6)
Law (# of States)
Decriminalized (5)
Medical (7)
Decriminalized + medical (11)
Decriminalized + recreational/medical (4 + D.C.)
Law (# of States)
ZT for THC/metabolites (9)
ZT for THC (3)
THC per se (5)
Reasonable inference (1)

Source: State Highway Safety Offices.