DUI of Marijuana – Laws, Penalties & Defenses

DUI of marijuana is operating a motor vehicle when your driving ability is impaired from being under the influence of the drug. While the recreational use of marijuana is now legal in a number of states, including California, DUI of marijuana remains a crime across the United States.

In California, the penalties for DUI of marijuana are virtually identical to DUI of alcohol. However, unlike with alcohol, there is no “per se” limit as to the concentration of THC you can have in your blood: This allows for more opportunities for us to challenge a DUI marijuana charge in court.

The penalties for DUIs involving cannabis in California are summarized in the following chart:

DUI Charge	Possible Penalties in California
1st DUI	Up to 6 months of jail; $390-$1,000 fine; 3 or 9-month DUI school; 6 – 10 months suspended license (convertible to restricted license).
2nd DUI	96 hours – 1 year of jail; $390-$1,000 fine; 18 or 30-month DUI school; 2 years suspended license (convertible to a restricted license after 12 months).
3rd DUI	120 days – 1 year of jail; $390-$1,000 fine; 30-month DUI school; 3 years revoked license (restricted license possible after 18 months).
Misdemeanor DUI w/injury	5 days – 1 year of jail; $390-5,000 fine (plus restitution to injured parties); 3, 18 or 30-month DUI school; 1 – 3 years revoked license.
Felony DUI	16 months, 2 years or 3 years of prison; $390-$1,000 fine; 18 or 30-month DUI school; 4 years revoked license.
Felony DUI w/injury	16 months-16 years of prison; $1,015-5,000 fine (plus restitution to injured parties); 18 or 30-month DUI school; 5 years revoked license.

To help you better understand Vehicle Code 23152(f), our California DUI defense lawyers discuss the following, below:

• 1. Criminal Elements
• 2. Evidence
• 3. Chemical Tests
• 4. Test Reliability
• 5. Refusing the Test
• 6. Must police offer the test?
• 7. Marijuana Effects
• 8. Penalties
• 9. Defenses
• 10. Related Crimes
• Additional Resources

1. Criminal Elements

The crime of driving under the influence of marijuana is outlined in California Vehicle Code 23152(f).¹ This section states:

“It is unlawful for a person who is under the influence of any drug to drive a vehicle.”²

For you to be convicted of DUI of cannabis in California, prosecutors must prove beyond a reasonable doubt the following elements of the jury instructions:

1. You drove a vehicle;³ and
2. While driving, you were under the influence of drugs and/or alcohol.⁴

Let’s take a closer look at some of these elements.

“Driving” a Vehicle

For purposes of California DUI law, the word “drive” carries its usual, everyday meaning.⁵

An officer can also arrest you for DUI even if they did not see you drive. The prosecution may then prove that you drove from circumstantial evidence.⁶

Example: A California Highway Patrol officer comes across a car parked at an angle on the shoulder of a highway. The car has one occupant, Darryl. Even though the officer did not see Darryl drive the car, she can arrest him. The car could only have gotten onto the shoulder if someone had driven it there.⁷

Being Behind the Wheel Is Not Enough

Even though circumstantial evidence can be proof of driving, merely sitting behind the wheel of a car is not enough – even with the engine running.⁸

Example: An LAPD officer sees Alfred get into his car and turn on the ignition after smoking a joint outside of a bar. Since Alfred never actually drove the vehicle, there is no probable cause for a DUI arrest.⁹ He could have been sitting in the running vehicle simply to get warm or to listen to the radio.

“Under the Influence”

You are “under the influence” of marijuana when:

1. As a result of consuming cannabis,
2. Your mental or physical abilities are so impaired,
3. That you are unable to drive a vehicle with the caution of a sober person, using ordinary care, under similar circumstances.¹⁰

Whether you were under the influence is an issue to be decided by a “trier of fact.” The trier of fact can be:

• A jury, or
• If you prefer, a judge (in a California “bench” trial).

The jury or judge will decide whether the prosecutor has proved beyond a reasonable doubt that you drove under the influence of marijuana.

2. Evidence

Proving a DUI of marijuana presents serious challenges for a prosecutor. This is because, unlike alcohol, ¹¹ there is no “legal limit” for marijuana under California law.¹²

In this respect, California is different from some other states. Some states restrict the amount of THC that can be in your bloodstream.¹³

THC (short for “delta-9-tetrahydrocannabinol”) is the main psychoactive ingredient in marijuana.¹⁴ It is what makes you feel “stoned” or “high.”

Some strains of weed are low in THC and high in a substance known as “cannabidiol” (“CBD”). CBD is a non-psychoactive substance found in marijuana.

Many medical marijuana users choose high CBD strains to obtain the health benefits of cannabis without getting high. ¹⁵

Chemical Tests for Cannabis Are Not Reliable

Some of the reasons why California has no legal limit for THC include that:

1. Chemical tests for THC are not yet reliable enough, and
2. Experts cannot agree on how much marijuana is too much for driving.¹⁶

We discuss these issues at length in Sections 4 and 5, below. In short, a chemical test alone is usually not sufficient to convict you of DUI. Moreover, studies have shown field sobriety tests to be unreliable as well in proving impairment from marijuana.

You Can Be Convicted Without a Chemical Test

Chemical test results are not necessary to convict you of DUI of marijuana.¹⁷ They are just one piece of evidence the prosecutor can use to show impaired driving. ¹⁸

This means a prosecutor can charge you with driving under the influence even if you are not offered, or you refuse to take, a chemical test.

What Other Evidence Can Be Used to Convict Me of DUI of Cannabis?

In addition to (or instead of) chemical test results, evidence of driving under the influence of marijuana may include:

• Your driving pattern;
• Your statements to the police officer;
• Your performance on Field Sobriety Tests (FSTs);
• The presence of marijuana or drug paraphernalia in your car or on your person;
• Physical symptoms of intoxication, such as:
  • Dilated pupils,
  • Rapid heart rate,
  • Rapid breathing,
  • The odor of marijuana coming from your body,
  • Red eyes,
  • Dry “cotton” mouth, and/or
  • Slowed reaction time; and/or
• Evidence showing that you are addicted to marijuana. ¹⁹

Drug Recognition Experts

Most of the evidence of impairment will be established through testimony from the arresting officer. Though some California law enforcement agencies also employ a “Drug Recognition Expert” (DRE).²⁰

The DRE will examine you and may testify at trial about your physical symptoms of impairment.

3. Chemical Tests

When you are arrested for driving under the influence, you must be offered the choice of either a DUI breath test or a DUI blood test.²¹

Most drivers choose a breath test, which is less invasive than a blood test. However, you may be required to take a blood test if the officer reasonably believes that:

• You are under the influence of marijuana or other drugs, and
• A blood test will reveal the presence of drugs.²²

This typically happens in the following situations:

• A breath test comes up negative, or low, for alcohol,
• The officer smelled marijuana on you,
• The officer observed physical signs of intoxication, and/or
• The officer found drugs and/or drug paraphernalia in your car.

If you cannot take a blood test because of a medical condition (such as hemophilia) – or if blood testing is not available – you may take a urine test instead. ²³

4. Test Reliability

There are three problems with using chemical tests to prove that you drove under the influence of marijuana:

1. Chemical tests do not indicate reliably when cannabis was used;
2. They do not indicate reliably how much was used; and
3. There is no consensus on how much marijuana leads to impaired driving.²⁴

Test results can also vary depending on which type of test is used.

Let’s take a quick look at the problems associated with blood, urine and saliva tests.

Blood Tests

The most common chemical test in a DUI of marijuana case is a blood test. Blood tests look directly for the presence of delta-9-tetrahydrocannabinol (“THC”).

Though unlike alcohol, THC is not metabolized at a steady rate, especially when smoked. Instead, the THC level can peak in as little as ten minutes, after which it declines rapidly.²⁵

By the time you have been arrested and a blood sample has been taken, most (but not all) of the THC is gone.²⁶

THC Is Detectable for Up to a Month

Unlike alcohol, which is water-soluble, THC is fat-soluble. This means that once ingested, it is stored in your body’s fatty tissues.

These fatty tissues can leach stored THC back into the blood for up to one month or longer. So a blood test for THC can be positive even if you have not recently smoked or consumed marijuana. ²⁷

What is more, low THC levels in the blood can result either from:

• Relatively recent use (for example, smoking within the prior 1 to 3 hours), or
• Chronic use (even without any recent ingestion).²⁸

So a positive blood test is not clear evidence during a VC 23152 violation.

Urine Tests

A urine test does not check directly for THC. Instead, it checks for inactive metabolites found in marijuana.²⁹

These inactive metabolites can be detected in urine long after consumption. Some estimates suggest they can be detected for up to four weeks in chronic users.³⁰

Since these metabolites do not cause impairment, a positive urine test does not prove that you were “under the influence” of marijuana. It merely indicates that you consumed cannabis within the last month or so.³¹

High CBD / Low THC Strains Are Prone to False Positives

High CBD/low THC marijuana can cause misleading urine test results.³² Even though this type of cannabis does not get you high, it still contains cannabis metabolites other than THC. These metabolites can trigger a “false positive” result on a DUI urine test.

Oral Swabs / Saliva Tests

Some California counties have begun using a roadside “oral fluid” (saliva) test for marijuana.³³ The test is performed by swabbing the insides of your mouth with a cotton swab.

Such swabs are relatively non-invasive. They can also narrow the window of marijuana use to a few hours. ³⁴

Though while saliva tests are good at detecting the presence of marijuana, they are not reliable indicators of how much was consumed or whether you were impaired.³⁵

Saliva tests have also not yet been ruled admissible in driving under the influence cases.

So at present, law enforcement agencies that use saliva tests do so as a preliminary screening test only. If your saliva tests positive for THC, the officer will most likely then arrest you and require a blood test.

5. Refusing the Test

Under California’s “implied consent” law, you must consent to a chemical test after a DUI arrest.³⁶

Prior to an arrest – such as during a traffic stop or DUI checkpoint – an officer may ask you to:

• Blow into a hand-held Breathalyzer for a preliminary alcohol screening (PAS) test,
• Submit to a saliva swab to test for marijuana and/or other drugs, and/or
• Perform one or more field sobriety tests (such as the “one-leg stand” test).

As long as you have not yet been placed under arrest, you may decline to take all these tests.³⁷

Penalties for Refusing a Post-Arrest Chemical Test

If you were arrested for DUI, refusing to take a chemical test triggers an automatic one-year suspension of your driver’s license. This stands even if you are not charged with, or are later found “not guilty” of, driving under the influence. ³⁸

Other consequences of a chemical test refusal include increased penalties if you are later convicted of DUI. For a first-time conviction, these enhanced penalties include:

• 2 extra days in jail, and
• 9 months of DUI school instead of the usual 3-month program.³⁹

6. Must police offer the test?

Police are not required to offer you a chemical test. This is important because, as we discussed above, THC and other metabolites remain in the blood and urine for a long time. So a negative chemical test is strong evidence that you did not use marijuana.

If you want such evidence, you must request a chemical test. The police must allow you to take one if you are willing to pay for the test. ⁴⁰

7. Marijuana Effects

THC can produce alterations in

• motor behavior,
• perception,
• cognition, and
• memory.⁴¹

Though so far, studies have not shown a consistent correlation between THC use and driver impairment.

In fact, in some studies, drivers have been least impaired when THC concentration in the blood is at its highest. Plus some drivers have shown more significant impairment when their THC levels were low.⁴²

This may simply be because drivers tend to drive more cautiously after significant marijuana use. Meanwhile, according to National Highway Traffic Safety Administration (NHTSA), having a blood alcohol content of only 0.05% increases the risk of a crash by 575%!⁴³

8. Penalties

Penalties for DUI of marijuana are the same as for an alcohol DUI. Unless a serious accident is involved, it is usually charged as a misdemeanor. (It does not matter whether you used the drug medicinally or recreationally.)

If someone is seriously injured, the offense becomes a California “wobbler.” A “wobbler” can be charged as either a misdemeanor or a felony, at the prosecutor’s discretion.

Misdemeanor Punishment

As a first offense, punishment for any California DUI conviction (including DUI of marijuana) can include:

• Informal (summary) probation for 3 to 5 years,
• Between 96 hours and 6 months in county jail,
• A fine of between $390 and $1,000, and/or
• A 6-month driver’s license suspension. ⁴⁴

These penalties increase slightly for a second or third conviction.

Felony Punishment

In rare cases, DUI of marijuana can be charged as a felony. This can occur if:

• An accident due to cannabis use results in injury (or death) to a third party, ⁴⁵ or
• You have 3 or more prior DUI or wet reckless convictions within the last 10 years, or
• You have even 1 prior felony conviction within the 10 preceding years.⁴⁶

Felony penalties for driving under the influence can include:

• Felony (formal) probation, and/or
• A California state prison sentence, and/or
• A 1-year or longer suspension of your driver’s license.⁴⁷

If a third party dies due to your impaired driving, you could conceivably be charged with:

• Gross vehicular manslaughter while intoxicated (Penal Code 191.5(a) PC), or even
• Second-degree murder – known as “Watson” murder or DUI murder.⁴⁸

9. Defenses

Many legal defenses to driving under the influence of alcohol can also be used to fight DUI marijuana charges, including:

• You did not drive (“no driving” defense),
• The DUI traffic stop and/or arrest was unlawful, and/or
• The police failed to conduct a chemical test in accordance with California Title 17 regulations.

Though a few defenses are specific to DUI marijuana, as discussed below.

You Have Not Used Marijuana

Marijuana’s metabolites are unique. As a result, it is unlikely you will test positive if you have not used it within the last month or so.

A negative chemical test is, therefore, usually a good indication that you are not guilty of DUI of marijuana. However, even a “positive” result can be inaccurate because of:

• Flaws with the chemical test procedures or equipment, or
• Certain medications, such as proton pump inhibitors (for example, Protonix) for gastrointestinal reflux disease.⁵⁰

You should tell us about all drugs and supplements you use – whether prescription, over-the-counter, or illegal.

You Recently Used But Are No Longer High

Chemical tests can show whether you used marijuana, but not how long ago it happened.

Occasional users may test positive for up to 12 hours after smoking it. Moderate users may test positive for several days after the last use.⁵¹ Meanwhile, chronic users may test positive for a month or more after using.⁵²

This is why prosecutors in DUI of drug cases cannot rely on chemical tests as “smoking guns.” We will make this clear to the prosecutor and – if your case goes to trial – to the judge or jury.

You Used, But Your Driving Was Not Impaired

Even if the prosecutor can prove you recently used marijuana, it does not mean you will be convicted.

The California legislature has not set a “per se” blood THC limit like the .08% limit it set for blood alcohol content (BAC).⁵³ This means that the prosecutor must prove beyond a reasonable doubt that you were actually impaired when you drove.⁵⁴

As Santa Ana criminal and DUI defense lawyer John Murray⁵⁵ explains:

“No one agrees exactly how much THC in the blood makes a driver ‘impaired.’ The burden is on the prosecutor to prove that someone’s drug use actually affected his or her ability to drive safely. With marijuana especially, that can be difficult to do.”

However, note that it is a crime in California to drive while addicted to any drug.⁵⁶ Addicted driving is considered a form of California DUI and carries the same penalties.

Prosecutors rarely bring charges for driving while addicted to a drug. However, a zealous prosecutor who cannot prove you were impaired might try instead to prove you were addicted.

Non-Defenses

It is not a defense to DUI drug charges that you had the legal right to use marijuana. This is true even if you were using the drug under California’s medical marijuana laws.⁵⁷

If a drug impairs driving, it does not matter whether it is legally or even medically necessary. If your ability to drive safely is impaired, you may not drive.

It is also not a defense to the charges that your impairment was caused in part by something other than drugs.

For example, perhaps you were using marijuana to treat a migraine, and the migraine was the main cause of the impairment. If your impairment resulted in even a little from using marijuana, you can be found guilty.⁵⁸

10. Related Crimes

Driving in Possession of Marijuana — Vehicle Code 23222

Driving with an open container of marijuana in the car is illegal under California Vehicle Code 23222(b).⁵⁹

This law does not apply, however, to open containers of weed in the trunk of the vehicle.

Violation of VC 23222(b) is an infraction carrying up to $100.

Unlawful Possession of Marijuana for Personal Use

Effective January 1, 2018, adults age 21 and over may lawfully possess the following quantity of marijuana in California:

• Up to 28.5 grams of flowers, stems, seeds, etc., or
• Up to 8 grams of concentrated cannabis (hashish).⁶⁰

Possession of marijuana in more than this amount is a misdemeanor for anyone age 18 or older. It is punished by:

• Up to 6 months in county jail, and/or
• Up to $500 in fines.⁶¹

Possession of smaller quantities by people aged 18 to 20 – or possession of any quantity by someone under 18 – is an infraction. Depending on your age and the amount possessed, it is punished by:

• Up to $100,
• Drug education or counseling, and/or
• Community service.⁶²

Additional Resources

For more information, refer to the following:

• Field sobriety tests may be insufficient in DUI cases involving cannabis: UCSD study – Article by 7 San Diego NBC.
• For police, catching stoned drivers isn’t so easy – Article in Los Angeles Times.
• How does law enforcement know if you’re too high to drive? What California law says – Article in The Sacramento Bee.
• Marijuana and driving: California lacks legal THC limit – Article by CBSNews Los Angeles.
• Drug-Impaired Driving – Legal overview by the California Office of Traffic Safety.

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