Yes, you can get a DUI for driving high. Every state’s DUI statute covers marijuana alongside alcohol, and in every state a marijuana-impaired driving conviction carries criminal penalties: jail exposure, fines, license suspension, and a record that follows you for years. What makes marijuana DUI different from alcohol DUI is the science. There is no roadside breath test for THC, no universally accepted impairment threshold, and no reliable way to tie a blood test result to how high you were at the moment you were driving. That gap does not stop arrests or convictions. It just shapes how the case gets built and how it can be fought.
How States Decide You Were Driving High
Three approaches are in play, and which one you face depends entirely on where you were stopped.
Six states use per se THC limits, setting a specific blood concentration between 1 and 5 nanograms per milliliter that automatically qualifies as impairment. Colorado uses a related “reasonable inference” rule: a jury can presume impairment above 5 nanograms per milliliter, but the driver can argue otherwise.1National Highway Traffic Safety Administration. Drug-Impaired-Driving Laws
Roughly 14 states apply zero tolerance, making it illegal to drive with any detectable THC or its metabolites in your system. This is where regular users get caught sober. THC metabolites can stay in blood for days or weeks after the high fades, and under a zero-tolerance regime a positive test alone can support conviction.
The remaining states use an impairment-based standard. There is no magic number. Prosecutors have to prove through officer observations, driving behavior, witness testimony, and test results that marijuana actually impaired your driving. That gives defendants more room to push back, but it also lets officers build cases on circumstantial evidence.
What Happens at the Traffic Stop
Officers usually start with the Standardized Field Sobriety Tests developed by NHTSA: the Horizontal Gaze Nystagmus test, the Walk and Turn, and the One-Leg Stand.2National Highway Traffic Safety Administration. DWI Detection and Standardized Field Sobriety Testing SFST Participant Manual These were designed for alcohol, and they do not translate cleanly. A 2023 clinical trial found that nearly half of participants who received a placebo were still classified as impaired by trained officers.3National Center for Biotechnology Information. Evaluation of Field Sobriety Tests for Identifying Drivers Under the Influence of Cannabis
Because the standard tests struggle with cannabis, many departments call in a Drug Recognition Expert. A DRE runs a longer 12-step evaluation covering vital signs, pupil reactions in a dark room, muscle tone, and additional divided-attention tasks.4National Highway Traffic Safety Administration. Drug Evaluation and Classification Program Participant Manual The DRE’s opinion about what drug category is causing impairment often becomes key testimony at trial.
Chemical testing is where cases are usually made or broken. There is no quick roadside THC breath test, so officers who suspect drug impairment typically transport you to a facility for a blood draw. As of 2021, 24 states allowed officers to collect saliva samples as a less invasive alternative. Oral fluid devices produce fast results, but NHTSA-funded testing found that three of five commercial devices failed to meet recommended performance standards.5National Highway Traffic Safety Administration. Drug-Impaired Driving Emerging Issues A positive saliva result does not prove impairment on its own; officers use it to decide whether to pursue a blood draw.
The deeper problem runs through every method. THC can be detected in blood long after the effects fade, especially in frequent users, so a 3-nanogram result tells you little about whether the driver was actually high behind the wheel. That disconnect between detection and impairment is the biggest scientific weakness in marijuana DUI enforcement, and it is the issue defense attorneys press hardest.
If You Refuse the Test
Every state has an implied consent law. By holding a driver’s license, you have already agreed to submit to chemical testing after a lawful DUI arrest. Refusing does not make the case go away. It usually makes things worse.
Refusal triggers an automatic administrative license suspension on top of any criminal penalties, with the length varying by state and prior offenses. Prosecutors can also use the refusal as evidence at trial, arguing that you declined because you knew the results would incriminate you.
There is a constitutional limit worth knowing. In Birchfield v. North Dakota, the Supreme Court held that states can require warrantless breath tests after a DUI arrest, but blood tests are more intrusive and generally require a warrant, and states cannot impose criminal penalties for refusing a warrantless blood draw.6Justia. Birchfield v North Dakota, 579 US (2016) Civil penalties like license suspension still apply. Because marijuana detection relies on blood or saliva rather than breath, this distinction matters more in cannabis cases than in alcohol cases.
Penalties for a Marijuana DUI
A first-offense marijuana DUI is a misdemeanor in most states, with penalties that track a first alcohol DUI closely. Specifics vary by jurisdiction, but most first offenders face some mix of the following:
- Jail time, often starting with a mandatory minimum of 24 hours to several days and maximum misdemeanor exposure of up to a year
- Fines and court costs that commonly run from $500 to $10,000 once surcharges and program fees are added in
- License suspension of 90 days to one year, longer for repeat offenses or test refusal
- A mandatory substance abuse assessment and any treatment it recommends
- Probation lasting one to three years
Repeat offenses escalate hard. A second or third marijuana DUI can be charged as a felony in many states, with prison time measured in years, much larger fines, and longer license revocations. Some states move to felony on a second conviction; others wait for a third or fourth. If impaired driving causes an accident that injures or kills someone, felony charges and prison are on the table regardless of whether it is your first offense.
Hiring a private defense attorney for a drug DUI typically runs between $2,000 and $7,500, with complex or trial cases going higher.
A Medical Marijuana Card Does Not Protect You
A valid medical marijuana prescription or patient card is not a DUI defense. DUI laws focus on whether a substance impaired your driving, not whether you were legally allowed to use it. The same logic applies to prescription painkillers: a lawful oxycodone prescription does not shield you from a DUI if the drug impaired you behind the wheel.
A medical card might influence plea discussions in a close case, particularly where no accident occurred and impairment is genuinely contested. At trial, it has no recognized force in any state.
Commercial Drivers Face a Separate Rulebook
If you hold a CDL, a marijuana DUI is career-ending in a way ordinary drivers do not face. Federal law applies zero tolerance: the Department of Transportation requires marijuana testing for all safety-sensitive transportation employees, with no acceptable amount of THC.7eCFR. 49 CFR Part 40 – Procedures for Transportation Workplace Drug and Alcohol Testing Programs State legalization does not change that.
A first DUI conviction while operating a commercial vehicle triggers a minimum one-year CDL disqualification, or three years if hazardous materials were involved. A second violation is a lifetime disqualification, though federal regulations allow possible reinstatement after at least 10 years.8Office of the Law Revision Counsel. 49 USC 31310 – Disqualifications These federal rules apply even when the DUI happens in your personal car on your own time, and the conviction gets reported to the FMCSA clearinghouse where any prospective employer will see it.
Defenses Worth Taking Seriously
The scientific uncertainty gives defense attorneys more to work with in cannabis cases than in alcohol cases. No defense is a guaranteed winner, but several routinely matter.
Challenging the field sobriety tests is often the starting point. Because the tests were validated for alcohol and sober participants fail them so often in controlled studies, defense counsel can argue they are too subjective to prove marijuana-specific impairment, especially when no chemical test result backs up the officer’s observations.3National Center for Biotechnology Information. Evaluation of Field Sobriety Tests for Identifying Drivers Under the Influence of Cannabis
Chemical test results are vulnerable for the same reason they are powerful: THC lingers. In impairment-based states, a positive blood test does not automatically prove you were high at the wheel. Attorneys also challenge chain of custody, lab technician qualifications, and delays between the stop and the draw.
Constitutional violations can end a case outright. If officers lacked probable cause for the stop, or conducted a blood draw without a warrant or valid consent, the evidence can be suppressed under the Fourth Amendment.9Legal Information Institute. Fourth Amendment Birchfield reinforced that blood tests generally require a warrant, giving defendants a concrete standard to invoke.6Justia. Birchfield v North Dakota, 579 US (2016)
Alternative explanations also matter. Fatigue, medical conditions, prescription medications, anxiety during a police encounter, and uneven road surfaces can all produce signs officers attribute to marijuana. In impairment-based states where prosecutors cannot just point to a THC number, those explanations can create reasonable doubt.
Long-Term Consequences
Sentencing is only the start. A marijuana DUI conviction creates ripple effects on insurance, employment, and your record that last years.
Insurance hits first. Most states require drivers convicted of DUI to carry SR-22 or FR-44 high-risk certification, usually for three years after license reinstatement and up to five for repeat offenders. The filing itself is minor, but the underlying premiums typically double or more for the duration.
Employment consequences reach beyond commercial driving. A DUI shows up on background checks and can disqualify you from positions that require a clean driving record, security clearance, or professional licensing. Healthcare, education, law enforcement, and finance often treat it as a serious red flag. If your job involves any driving, your employer’s insurer may refuse to cover you.
The conviction also becomes a prior offense for future sentencing. Most states look back five to ten years when deciding whether a new DUI counts as a first, second, or subsequent offense. That earlier conviction on your record means the next one carries mandatory jail time and the possibility of felony charges, even if the first ended in probation and a fine.