Driving under the influence of marijuana is a serious offense in California—even though cannabis is legal for both recreational and medicinal use. The key issue isn’t whether marijuana use is lawful; it’s whether the driver was impaired while operating a vehicle. Unlike alcohol, marijuana has no universally agreed-upon legal limit for THC in the bloodstream, which makes these cases complex and highly dependent on interpretation.
Understanding How Marijuana DUI Is Charged
California law prohibits driving under the influence of any drug, including cannabis. For prosecutors to charge someone with a marijuana DUI, they must prove two things: that the person was driving a vehicle, and that they were under the influence of marijuana to the point of being impaired at the time of driving.
Because marijuana affects each person differently, and THC can stay in the body for days or even weeks after use, law enforcement and prosecutors must rely on circumstantial and observational evidence. This can include erratic driving, bloodshot eyes, the smell of marijuana, slowed reaction times, and field sobriety test results.
Common Evidence Used in Marijuana DUI Cases
Police officers typically rely on several types of evidence to build a marijuana DUI case:
-
Driving behavior such as weaving, speeding, or abrupt stops
-
Admission of marijuana use or visible paraphernalia in the vehicle
-
Performance on field sobriety tests (FSTs)
-
Physical symptoms like red eyes, drowsiness, or delayed responses
-
Evaluations from a Drug Recognition Expert (DRE)
-
Blood or urine tests showing the presence of THC
It’s important to remember that testing positive for marijuana does not automatically prove impairment. That’s one of the biggest differences between alcohol and cannabis DUI cases.
Penalties for a Marijuana DUI in California
Even a first-time marijuana DUI conviction can come with serious consequences. These penalties can escalate quickly with prior offenses or if the DUI involved an accident or injury.
For a first offense, you may face:
-
Jail time ranging from a few days to six months
-
Fines and court fees
-
A six to ten-month driver’s license suspension
-
Mandatory DUI education programs
-
Probation that can last several years
Repeat offenses can result in longer jail time, extended license suspension, larger fines, and stricter court-ordered programs. In more serious cases—such as when someone is injured—a marijuana DUI can be charged as a felony, carrying state prison time and lasting consequences.
Defending Against a Marijuana DUI Charge
There are several legal strategies that a skilled attorney can use to challenge a marijuana DUI case. Each case is unique, but here are some of the most common and effective defenses:
Lack of Impairment
Just because THC is present in the blood doesn’t mean the driver was impaired. Frequent users may have residual THC in their system for days or weeks without any active impairment.
Inaccurate or Unreliable Testing
Blood and urine tests do not always accurately measure impairment. THC can linger in the body long after the effects have worn off. In some cases, lab results may be flawed or mishandled.
Improper Police Procedures
If the officer didn’t have a valid reason to pull you over or failed to follow proper arrest procedures, your case could be dismissed. This includes unlawful searches or arrests made without probable cause.
Faulty Field Sobriety Tests
FSTs are often used to determine impairment, but their reliability is questionable—especially for marijuana. Factors like fatigue, nervousness, or medical conditions can affect your performance.
Unqualified Drug Recognition Expert (DRE)
If a DRE wasn’t properly trained or certified, or their evaluation was incomplete, their findings may be challenged in court.
Contamination or Chain of Custody Issues
Any errors in how blood or urine samples were stored, transported, or tested can cast doubt on the prosecution’s entire case.
What To Do If You’re Charged with a Marijuana DUI
Being arrested for a marijuana DUI can be overwhelming, but you’re not without options. Here’s what you should do immediately:
-
Stay calm and do not admit guilt or make any unnecessary statements to law enforcement
-
Document every detail you remember about the traffic stop and arrest
-
Do not miss any court dates or DMV deadlines
-
Contact a criminal defense attorney experienced in drug-related DUI cases as soon as possible
Can You Be Convicted With THC in Your System but No Impairment?
Yes, it’s possible to be charged based on the presence of THC alone, but for a conviction, the prosecution must prove that you were actually impaired while driving. Without strong evidence of impaired driving, a conviction can be very difficult to obtain.
How Long Does Marijuana Stay in Your System?
THC can be detected long after the effects have worn off:
-
Occasional users: up to a few days
-
Regular users: several days to weeks
This delay between use and detection makes it difficult for prosecutors to prove that someone was high at the time they were driving.
Does Having a Medical Marijuana Card Help?
Having a medical marijuana card does not excuse driving under the influence, but it can sometimes help explain the presence of THC in your system and support a defense that you were not impaired.
Why Fighting a Marijuana DUI Charge Is So Important
A conviction for marijuana DUI can lead to more than just legal penalties. It can affect your employment, your insurance rates, your professional licenses, and your future. Having a knowledgeable attorney on your side can make a huge difference in the outcome of your case.
From challenging test results to questioning the validity of the traffic stop, there are many strategies an experienced defense attorney can use to protect your rights and fight for a dismissal or reduction of charges.
Facing a Marijuana DUI in California?
Contact Southwest Legal Today. At Southwest Legal, we understand how stressful and confusing it can be to face a marijuana DUI charge—especially in a legal environment where cannabis use is common and accepted. Our experienced DUI defense attorneys know how to challenge unreliable testing, improper police procedures, and weak evidence of impairment.
Don’t leave your future to chance. Call us today for a free consultation. We’ll review your case, explain your options, and build a strategic defense tailored to your situation. Your rights matter. Let us help you protect them.
