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Driving Under the Influence of Marijuana

Driving under the influence (DUI) of marijuana is a crime covered under California Vehicle Code §23152 (f). It makes it a criminal offense to drive a vehicle while your driving ability is impaired due to being high on marijuana. Although recreational use of marijuana is legal in California, DUI of marijuana is still a criminal offense in the United States.


First Time DUI – up to 6 months jail, fine of $390 to $1000, 3- or 9-months DUI school, 6 to 10 months license suspension (convertible to restricted license)

Second DUI – 96 hours to 1-year jail time, fines of $390 to $1000, 18- or 30-months DUI school, 2 years license suspension (convertible to restricted license after 12 months)

Third DUI – 120 days to 1-year jail time, fines of $390 to $1000, 30 months DUI school, 3 years license revocation (restricted license possible after 18 months)

Misdemeanor DUI with Injury – 5 days to 1-year jail, fine of $390 to $5000 (plus restitution to injured parties) 3-, 18-, or 30-months DUI school, 1 to 3 years license revocation

Felony DUI – 16 months, 2 years, or 3 years state prison; fine of $390 to $1000, 18- or 30-months DUI school; 4 years license revocation

Felony DUI with Injury – 16 months to 16 years prison, fine of $1015 to $5000 (plus restitution to injured parties), 18- or 30-months DUI school, 5 years license revocation

To help give you a better understanding of DUIs as covered under Vehicle Code 23152 (f), our DUI defense attorneys will discuss some important matters you should know in the following article.

1. Vehicle Code §23152 (f) - Driving Under the Influence of Drugs

A person is considered to be driving under the influence of drugs when:[1]

  • He or she drives a vehicle; and
  • He or she is under the influence of any drug which includes marijuana or cannabis;
  • His or her mental or physical abilities are so impaired by such drug(s) that he or she is unable to operate a vehicle with the caution of a sober person, using ordinary care under similar circumstances.

1.1 Defining “Driving”

In the context of a DUI, the word “drive” carries its usual everyday meaning. Proving that a defendant was driving is typically easy for the prosecution as most DUI of marijuana arrests happens during a traffic stop.

Keep in mind that an officer may still arrest a person for a DUI even if the officer did not see the person driving. This fact can be proven from circumstantial evidence.

Sitting Behind the Wheel Is Not Enough

Although driving may be proven by circumstantial evidence, merely sitting on the driver's side of a vehicle, even with the engine running, does not automatically constitute "driving".

A person is considered driving only when:[2]

  • He or she intentionally performs an action; and
  • Such action is one that is necessary to operate and direct the course of a motor vehicle.

1.2 Defining “Under the Influence”

A driver is under the influence of marijuana or cannabis when:

  • As a result of consuming marijuana or cannabis
  • His or her mental or physical abilities are so impaired
  • That he or she is unable to drive a vehicle with the caution of a sober person, using ordinary care, under similar circumstances

It is the prosecution’s job to convince the jury or judge (bench trial), that a defendant driver was under the influence of marijuana. The jury or judge determine whether the prosecution has proved beyond a reasonable doubt that the defendant driver was indeed under the influence.

2. Proving a DUI of Marijuana Charge

When it comes to DUI of alcohol, California law sets the legal limit to a BAC of 0.08%. However, when it comes to drugs, there is no such thing as a legal limit and even the slightest amount in a person's system can constitute a DUI. As such, it is harder for the prosecution to prove.

Unlike in other states, California does not restrict the amount of tetrahydrocannabinol or "THC" that can be found in a driver's bloodstream. THC is the main psychoactive ingredient in marijuana which causes a person to get high or "stoned."

Different strains of marijuana contain different levels of THC and cannabidiol or “CBD.” CBD is the non-psychoactive component in weed.

Medical marijuana users often chose strains that are high in CBD rather than THC, as CBD is the component that has health benefits, and it does not make a person high.

Reliability of Chemical Tests for Marijuana

California does not have a legal limit for THC due to several reasons, this includes:

  • Chemical tests for THC are not yet reliable
  • Experts do not agree on how much marijuana is “too much” in the context of driving

As such, a chemical test alone will not be enough to convict someone for DUI of marijuana.

Conviction Without Chemical Testing

Although chemical tests are not yet reliable, it is not necessary to convict someone for a DUI of marijuana. There are several ways to prove that a driver was impaired, and a chemical test is just one piece of evidence to prove such a fact.

Other Evidence Used To Convict Someone for DUI of Marijuana

The following includes, however not limited to, some of the evidence used to prove that a driver is impaired:

  • Driving pattern
  • Statement given to police officer
  • Performance in field sobriety tests (FST)
  • Presence of marijuana or other drug paraphernalia in the driver’s vehicle or person
  • Physical symptoms
  • Evidence of addiction to marijuana

Drug Recognition Experts

Drug recognition experts or DREs are law enforcement officers who are specially trained to identify persons who are under the influence of drugs.

DREs are currently under the California Highway Patrol. However, not all counties have DREs so they might not be called in depending on where a driver was arrested.

DREs and the 12-step Drug Impairment Evaluation

Once a DRE has been called onto the scene, they will now take over the DUI investigation. The DRE will conduct a 12- step evaluation to determine if a driver is indeed under the influence of drugs and this may include the following:

  • The DRE will confirm that the BAC of the driver is not above the legal limit
  • They will interview the arresting officer for more particular details about the case at hand
  • DRE will check the driver’s symptoms to check for possible drug use (pulse rate, pupil size, drug traces in the mouth or nostrils, muscle tone, and “track marks” for possible injection sites)
  • The DRE will also conduct an eye-tracking check similar to the horizontal gaze nystagmus used in field sobriety tests
  • The DRE will readminister the other field sobriety tests
  • The DRE will ask the driver about drug use
  • The DRE can ask the driver to submit to a blood test or urine test

Ideally, the DRE will conduct their examination in a well-lit area such as the police station. The DRE will then form an opinion on whether the driver is possibly under the influence of drugs.

Driver’s Rights During a DRE Investigation

A driver may exercise their fifth amendment right during the DREs investigation. This means a driver does not have to answer the DRE's questions or submit to further field sobriety tests conducted by the DRE.

Take note that there are no negative consequences for refusing to take a chemical test before an arrest. However, once a person has been arrested, refusing to submit to a chemical test could lead to increased penalties and mandatory driver's license suspension. However, a driver will always be required to take a chemical test, even before arrest, if the driver is:

  • Currently on DUI probation
  • Under the age of 21

The officer will arrest the driver once he or she has cause to believe that the driver was driving under the influence. At this point, the arresting officer does not necessarily need to read to the driver their Miranda rights. The reading of Miranda rights is only imperative when the driver is under custodial investigation. Custodial investigation means that:

  • The driver is already in custody and cannot freely leave
  • The police ask the driver questions intended to elicit an incriminating answer

3. Chemical Testing for Alcohol or Drugs

After being arrested, normally the driver is given the option to choose between taking a breath test or a blood test. Refusing to take any of these tests will constitute a "chemical test refusal" and could lead to increased penalties and mandatory driver's license suspension. The reason for this is because a person that has already been legally arrested cannot refuse to take a chemical test.

Blood Test

Under certain circumstances, a person can be legally required to take a blood test even after taking a post-arrest breath test. This can happen when:[3]

  • The officer has reasonable cause to believe that the driver was under the influence of drugs or a combination of drugs and alcohol
  • The officer has a clear indication that a blood test will reveal evidence of the person being under the influence

Normally, when a driver elects to take a breath test and the test reveals a BAC of 0.08% or above, the driver will be charged with any of the following:

  • Violation of Vehicle Code §23152 (a)
  • Violation of Vehicle Code §23152 (b) – BAC of 0.08% or above
  • Violation of Vehicle Code §23152 (d) – commercial vehicle DUI with BAC of 0.04% or higher
  • Violation of Vehicle Code §23152 (e) – taxi, limo, or ridesharing driver with BAC of 0.04% or higher
  • Violation of Vehicle Code §23140 – underage DUI with BAC of 0.05% or higher

However, if the driver reveals a BAC of below 0.08% after the post-arrest breath test, the officer can then order for a blood test. However, it is important to remember that a person's blood cannot be taken without the person's consent unless there is a warrant ordering for that person to provide a blood sample.[4]

4. Issues with Chemical Testing

There are three main issues when it comes to chemical tests in DUI of marijuana:

  • Chemical tests do not indicate when marijuana was used
  • Chemical tests do not indicate reliably how much was used
  • There is no consensus on how much marijuana consumption leads to impaired driving[5]

Depending on the type of test used, the results can vary greatly.

4.1 Blood Test

It is the most commonly used form of testing for drugs. A blood test will directly check for the presence of THC. Unlike alcohol, THC is not metabolized at a steady rate, especially when smoked. The THC level in the blood can peak in as little as 10 minutes, and then declines rapidly afterward.[6]

By the time a person has been arrested and a blood sample is taken, most of the THC is already gone.

THC Detectability

THC is fat-soluble, unlike alcohol which is water-soluble. This means that THC becomes stored in the body's fatty tissues.

These tissues can “leak stored THC back into the blood for up to a month or longer. This means that a blood test can still reveal a positive result even if a person has stopped consuming marijuana recently.

Therefore, a positive result from a blood test does not mean much when it comes to Vehicle Code §23152.

4.2 Urine Test

Urine testing does not check directly for THC. Instead, it checks for inactive metabolites found in marijuana.

These metabolites can be detected in the urine even long after use. It is even suggested that these metabolites can be detected from up to 4 weeks in chronic users.

As these substances by themselves do not cause impairment, a positive urine test does not necessarily mean that a person was under the influence at the time that they were driving. It is a mere indication that the person used cannabis within the last month or so.[7]

CBD False Positive

Strains that are high in CBD and low in THC are prone to giving misleading urine test results. Even if a type of strain does not get a person high, it will still contain the same metabolites that urine tests are testing for. They can lead to “false positive” results that do not accurately indicate that a person was indeed under the influence and impaired when driving their vehicle.

4.3 Saliva Test

Oral swabbing or saliva testing is now being used in some counties in California. The test is performed by swabbing inside the mouth (cheeks) of a driver with a cotton swab.

This form of testing is non-invasive. However, while it can detect the presence of marijuana, it does not reliably indicate how much was consumed or whether a driver was impaired.

Saliva tests have also not yet been ruled as admissible evidence in DUI cases.

Currently, saliva testing is used as a preliminary test but is not used as a post-arrest chemical test. If a driver tests positive with a saliva test, the usual protocol would be to order for a blood test afterward.

5. Chemical Test Refusal

As mentioned previously, if the driver refuses chemical testing post-arrest, the driver may face automatic suspension of his or her driver’s license and a mandatory county jail sentence of 48 hours if convicted of a DUI.

However, a driver may legally refuse to take a test before an arrest has been made.

Unlawful Arrest

There may be an instance when a person takes a chemical test and later on their respective attorney proves in court that the arrest was unlawful.

In such an event, the results of the test cannot be later on used as evidence. Also, a positive chemical test does not necessarily show that a driver was impaired at the time they drove.

6. Offering a Chemical Test

Police are not required to offer a chemical test. As discussed previously, due to the nature of THC and marijuana’s other metabolites, it will remain in the blood and urine for quite a while. So, a negative result would be a strong indication that a driver did not use marijuana.

If a driver wants to confirm that he or she did not take marijuana, they must affirmatively request for such a test. The police will allow the driver to take a test provided that the driver is willing to shoulder the expense for the testing.

7. Can Marijuana Impair Your Driving Ability?

This matter is still not yet agreed upon by experts.

Marijuana is still classified as a Schedule 1 narcotic under federal law. This in turn has resulted in a lack of research in terms of marijuana’s effects.

So far, what has been established is that THC can produce alterations in motor behavior, perception, cognition, and memory. However, there is no clear correlation yet between THC and driver impairment.

In some studies, drivers have shown that they are least impaired when the THC concentration is at its highest. While some drivers have shown significant impairment when THC levels were low.[8]

The important thing to note from all of this is that chemical testing does not prove beyond a reasonable doubt that a person’s driving is impaired by the usage of cannabis.

8. Penalties

The penalties are the same as that of a DUI of alcohol. Normally it is charged as a misdemeanor unless there was serious injury to a third party. If a third party is injured, it is charged as a "wobbler," meaning it can be charged as a felony or misdemeanor depending on the circumstances.

As a Misdemeanor

This offense is usually charged as a misdemeanor in California. The penalties are the same with a misdemeanor DUI of alcohol. The penalties can include:

  • 3 to 5 years of probation
  • Fines up to $1800 for a first offense
  • Mandatory alcohol or drug education program (DUI school)
  • Driver’s license suspension
  • Possible time in jail

As a Felony

This offense can be charged as a felony when:

  • The defendant already has one prior felony DUI conviction[9]
  • The defendant has committed DUI four or more times[10]
  • The DUI caused injury to a third party[11]

A felony DUID is penalized by:

  • up to 3 years in county jail (4 years if a third party was injured) AND/OR
  • A fine of up to $1000 (up to $5000 if someone was injured as a result of the DUID)

9. Defenses

The following are possible defenses in a DUI of Marijuana offense. However, defenses are not limited to the following and may vary depending on the circumstances of each case:

  • “No Driving” defense (driver did not drive)
  • Unlawful traffic stop/ DUI arrest
  • Violation of California Title 17 regulations
  • Driver has not used marijuana (residual metabolites still present in the system even if marijuana was not used recently)
  • Driver used marijuana but is no longer high when he or she drove (for DUI cases to prosper, impairment must have been when the driver was actually driving a vehicle)
  • Driver used marijuana but driving was not impaired

9.1 Legal Marijuana Use Is Not a Defense

Even if a driver is legally allowed to use marijuana, it is not a legal defense in terms of a DUI violation. (Ex. those allowed to use marijuana for medical purposes)

If cannabis use impairs a person’s driving, then that person becomes liable under California DUI laws even if marijuana is being used for medical purposes.

9.2 Other Causes of Impairment Not a Defense

Even if it is another factor, not marijuana, which caused the driving impairment, such a fact is still not a legal defense in a DUI case. (Ex. Marijuana was used for migraine management, and it is the migraine which actually caused the driving impairment)

10. Other Related Offenses

A person arrested for driving under the influence may be charged for other offenses in addition to or in lieu of the DUI:

  • Driving in possession of marijuana (Vehicle Code §23222(b))
  • Unlawful possession of marijuana for personal use: (1) possession of more than 28.5 grams of flowers, stems, or seeds; (2) possession of more than 8 grams of concentrated cannabis (hashish)

DUI of Marijuana Happens. Jail and Penalties Don’t Have To.

A DUI charge is a difficult thing to manage and navigate on your own. You will want to consult and secure the services of an experienced DUI defense attorney to assist you in navigating the legal complexities of these charges. You will want to avoid a conviction at all costs because it can have severe effects on your life. Although we are fielding inquiries from a lot of people in similar situations, we will do our best to put you in contact with an experienced lawyer from our firm.

If you need assistance with a DUI charge, do not hesitate to contact us at (626) 827-7222 to schedule your consultation with one of our experienced attorneys at no cost.

[1] CALCRIM 2110

[2] People v. Wilson 176 Cal. App. 3d Supp. 1 (1985)

[3] California Vehicle Code §23612 (a) (2) (C)

[4] Birchfield v. North Dakota 579 U.S. ____, 136 S.Ct. 2160 (2016)

[5] NPR, “Scientists Still Seek A Reliable DUI Test For Marijuana,” July 30, 2017.

[6] Id.

[7] Id.

[8] “Marijuana-Impaired Driving, a Report to Congress,” endnote 26, p. 7.

[9] California Vehicle Code §23550.5

[10] California Vehicle Code §23550

[11] California Vehicle Code §23554 and §23566

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