Vehicle Code Section 23152(a) VC
(California's Driving Under the Influence of Alcohol Law)


Vehicle Code 23152(a) VC
is the California DUI law that makes it a crime to operate a motor vehicle "under the influence" of alcohol. "Under the influence" means that your physical or mental abilities are impaired to the extent that you can no longer drive as well as a cautious sober person.In California, motorists can be prosecuted under this statute even if their blood alcohol concentration was below 0.08%. 

First, second and third offense Vehicle Code 23152(a) charges are prosecuted as misdemeanors in California. Penalties for a DUI conviction include misdemeanor probation, fines, DUI school, a drivers license suspension, and in some cases jail time and a requirement of installing an ignition interlock device on the offender's vehicle. 

Vehicle Code 23152(a) reads: "(a) It is unlawful for a person who is under the influence of any alcoholic beverage to drive a vehicle."

VC 23152(a) DUI is the "subjective" standard for DUI. In contrast, Vehicle Code 23152(b) sets forth the "per se" definition of DUI, which in most cases is driving with a blood alcohol content (BAC) of 0.08% or higher.

Below, our California DUI defense attorneys address the following:

VC 23152(a) is California's subjective "driving under the influence" law.

If, after reading this article, you would like more information, we invite you to contact us at Shouse Law Group.

1. What is the Legal Definition of Vehicle Code 23152(a) "Driving Under the Influence"?

Most people who get arrested for DUI in California ultimately get charged with two separate misdemeanor offenses:

  1. driving under the influence of alcohol, under California Vehicle Code 23152(a) VC, and
  2. driving with a blood alcohol content of 0.08% or greater, pursuant to California Vehicle Code 23152(b) VC.2

This article focuses on the "subjective" California misdemeanor offense of DUI per California Vehicle Code 23152(a) VC, in contrast to the "per se" offense of DUI with a blood alcohol content (BAC) of 0.08% or greater under Vehicle Code 23152(b) PC.

(And if you were driving under the influence of drugs, you will be charged under Vehicle Code 23152(e) VC, California's DUI of drugs law. This law applies regardless of of whether the drugs were illegal, as with driving under the influence of marijuana; prescription, as with driving under the influence of Vicodin; or even over-the-counter.)

Proving a DUI case

In order to convict you of driving under the influence, the prosecutor must prove the following two facts (otherwise known as "elements of the crime"):

  1. that you drove a motor vehicle, and
  2. that you were under the influence of alcohol at the time you drove.

And while this legal definition of VC 23152(a) DUI may seem pretty straight forward, it actually requires further explanation. Let's take a closer look at some of these terms to gain a better understanding of their legal definitions.


If an officer sees you driving, then the first element in the legal definition of Vehicle Code 23152(a) driving under the influence is obviously satisfied.

But what about when that's not the case? What if you were involved in an accident and the police only arrived on-scene after the fact? What if you were asleep in the car? What if the motor is running but you haven't "moved" the car?

"Driving" is an element of the crime of VC 23152(a) DUI that the prosecutor must prove.

These are the types of DUI scenarios that present themselves daily in Vehicle Code 23152(a) cases. It's not enough for the prosecutor to prove that you were under the influence--he/she must prove that you were driving under the influence.

California courts have held that some movement of the vehicle is required in order to constitute driving. And courts have further held that this movement may be proven by circumstantial evidence.3

"Circumstantial evidence" is any evidence that doesn't directly point to guilt, but can be inferred from the surrounding circumstances.

Example: Circumstantial evidence of driving was established when the defendant was found asleep in his car, obstructing the roadway. The defendant was the only person in the car, the car was not in a location where a car would normally be "parked", and...because the car didn't "magically" appear there...someone must have driven it to that location. Since there was no evidence suggesting that anyone else drove the car to that location...and no reason to believe that it wasn't the defendant who did so...the jury found that the defendant had been driving and so convicted him of DUI.4

Under the influence

According to California Vehicle Code 23152(a) VC, you are "under the influence" when, as a result of drinking alcohol,

"your physical or mental abilities are impaired to such a degree that you no longer have the ability to drive with the caution characteristic of a sober person of ordinary prudence under the same or similar circumstances".5

Simply put, this means that you are DUI under VC 23152(a) if the alcohol in your system has impaired your judgment to the point where you can't drive your car in the same way as someone who is not intoxicated.

You are considered to be "under the influence" under VC 23152(a) if alcohol impairs your ability to drive like a careful sober person.

That said, the manner in which you drove isn't conclusive of whether you were DUI. It is merely a factor that the jury can consider when looking at everything as a whole.6

2. How Does The Prosecutor Prove That I Was Driving Under The Influence?

California Vehicle Code 23152(a) is a "subjective" offense. This means that the entire prosecution team, which includes the

  • prosecutor,
  • arresting officer, and
  • prosecutor's "expert" witness, (who is typically a forensic toxicologist from a local law enforcement agency)

will attempt to prove that you were DUI by relying mostly on the officer's personal observations.

The prosecution's case against you begins when the so-called "investigating" officer testifies about everything that you did "wrong" in an effort to prove that you didn't have the mental or physical ability to drive your car safely (the legal definition of "driving under the influence" under VC 23152(a)).

This testimony will include observations about your driving pattern, your physical appearance, and your performance on the California DUI field sobriety tests (FSTs).

The officer's testimony

The arresting officer in a VC 23152(a) case will typically testify that you were

  • weaving or swerving,
  • driving erratically, or otherwise
  • unable to drive "with the caution characteristic of a sober person".

In Vehicle Code 23152(a) cases, the officer will almost always testify that you displayed the "objective signs of intoxication" which include (but are not limited to):

  • red and watery eyes,
  • slurred speech,
  • the odor of alcohol emitting from your breath, and
  • an "unsteady gait" (or wobbliness on your feet).
The arresting officer's testimony is often key to a California DUI case under VC 23152(a).

The officer in your driving under the influence case will also likely testify that you "failed to perform your field sobriety tests as explained and demonstrated".

Example: In the case of People v. Smith, the investigating officer testifies that when he pulled Smith over for speeding, Smith had red/watery eyes, smelled of alcohol, and was unsteady while performing his field sobriety tests.

Although it may seem like once the jury hears this testimony, Smith might as well throw in the towel, a skilled California DUI defense attorney not only expects this testimony but also knows the most effective ways to challenge it.

For example, in a Vehicle Code 23152(a) case, Smith's lawyer might elicit testimony that
  1. Smith had been working on his house outside in the sun all day,
  2. he was extremely tired from working,
  3. he was nervous and intimidated when he got pulled over, and
  4. he had drank some beer, which accounts for the odor of alcohol, but had not drank enough to put him "under the influence"
All of these factors could legitimately explain Smith's physical appearance and poor balance. And all of these factors were probably never even considered by the so-called "investigating" officer.

The effect of breath or blood test results

Even though the two major sections of California's DUI law--Vehicle Code sections 23152(a) and 23152(b) VC--are closely related, they are actually quite different.

Technically you may be guilty of driving under the influence (per VC 23152(a)) even though your blood alcohol concentration is less than 0.08% (the unlawful threshold set forth under VC 23152(b)). Similarly, you might have a blood alcohol concentration (BAC) at or above a 0.08% even though you may not be "under the influence" of alcohol.

That said, the prosecutor is usually permitted to introduce evidence of your BAC to support its case that you were driving under the influence for purposes of VC 23152(a). The jury instructions for Vehicle Code 23152(a) VC include an instruction that if your BAC tested at or above a 0.08%, the jury may (but is not required to) infer that you were under the influence.7

This is a major point of contention that your California drunk driving attorney will rebut, typically through the testimony of a defense expert witness. "Tolerance"--which is your personal sensitivity to alcohol--plays a large role in determining at what point you are "under the influence for purposes of VC 23152(a).

Most California law enforcement agencies testify that everyone is impaired at 0.08%--and some will testify that they believe the level is as low as 0.05%. But there are other experts who believe that the level is considerably higher -- even as high as 0.12%.

3. How Can I Fight VC 23152(a) DUI Charges?

There are a variety of California DUI defenses to Vehicle Code 23152(a) VC California's driving under the influence law that your lawyer could use on your behalf to fight your DUI charges. The most common include (but are not limited to):

Alcohol may not be the reason for your driving issues

If your driving was called into question, your California DUI lawyer will be sure to address the fact that sober people are responsible for the majority of traffic violations and accidents. Also, there may be non-alcohol related explanations for your driving mistakes, such as being lost or momentarily distracted.

Your DUI defense attorney can help identify the best legal defenses for fighting VC 23152(a) charges.

Objective signs and symptoms of intoxication can be caused by a number of factors

In a Vehicle Code 23152(a) case, if the officer testifies that you displayed physical signs and symptoms that were consistent with someone who had been drinking, your California DUI defense attorney will elicit testimony that

  • fatigue,
  • allergies,
  • the sun,
  • illness, and even
  • non-alcoholic beverages

can account for all of the "objective" signs of alcohol impairment that the officer observed.

However, if it is determined that you were intoxicated--and the above symptoms (such as fatigue or an illness like diabetes or epilepsy) simply contributed to your impairment--they will not serve as a defense to VC 23152(a) DUI.8

One note of caution: you and your DUI defense attorney should be careful about arguing that the physical signs of being under the influence were actually symptoms of drug withdrawal. This is because driving while addicted to a drug is a form of DUI under Vehicle Code 23152(c) VC--and carries the same penalties as VC 23152(a) DUI. 

Field sobriety tests don't accurately measure impairment

If your performance on the FSTs is described as "poor"--which will almost always be the case--your DUI defense lawyer will ask the officer to testify about all of the ways that you correctly performed the field sobriety tests.

This line of questions is designed to show the jury in your driving under the influence case that the number of things you did right far exceeded the number of things you did wrong. Your attorney will also challenge

  1. the validity of the specific tests that were administered (such as the the Horizontal Gaze Nystagmus (HGN) FST, the finger to nose FST, and/or the one-leg stand FST), and
  2. the manner in which the tests were administered.

The police didn't follow proper procedures

Every aspect of your California DUI investigation will be challenged. Your DUI attorney will call into question

As Ventura DUI defense attorney Darrell York12 explains:

"I've seen countless individuals charged with DUI--including DUIs where everything points to guilt--walk away clean due to shoddy police work, improperly maintained breath or blood testing instruments, and the skill of an experienced California DUI defense lawyer."


4. What are the Penalties for VC 23152(a) "Driving Under the Influence"?

The consequences of a violation of Vehicle Code 23152(a) VC California's driving under the influence law depend on whether you are convicted of your first, second, third, or subsequent offense.

Most first, second, and third-time DUIs are misdemeanors. Fourth and subsequent DUIs within a ten-year period are typically filed as felony drunk driving charges in California. Being involved in a DUI causing injury can also influence this determination.

California DUI penalties for misdemeanor violations of VC 23152(a) usually include (but are not necessarily limited to) the following:

  • informal probation for three to five years,
  • up to one year in a county jail (depending on whether it's your second or third offense),
  • a base fine of about $390 plus court assessments,13
  • participation in a court-approved DUI school,14
  • a minimum six-month California driver's license suspension15 (unless you initiate and win a California DMV DUI hearing),16
  • restrictions on your ability to travel to Canada,17 and
  • insurance repercussions, as California DUIs have an effect on car insurance policies.18

Aggravating factors

Additionally, aggravating factors such as

are all factors that could increase the consequences for a VC 23152(a) conviction.

DUI plea bargaining

Most Vehicle Code 23152(a) VC cases do not go to trial. This means that many cases are resolved during DUI plea bargaining negotiations.

Plea bargains are useful tools for both the defense and the prosecution in a "driving under the influence" case. A plea bargain allows the prosecutor to obtain a conviction and allows you to plead guilty to a reduced charge, and/or a lesser sentence.

Many VC 23152(a) cases are resolved through plea bargaining.

The most frequently reduced driving under the influence charges include

In certain very specific cases, you may be able to plea bargain your VC 23152(a) charge to Vehicle Code 23221 VC drinking alcohol in a vehicle.

This offense is charged when a driver was drinking alcohol in a vehicle on a public street (but the prosecutors are not able to prove that s/he met the legal definition of driving under the influence under Vehicle Code 23152(a) VC). VC 23221 is only an infraction.25

Finally, it's important to understand that even if you're convicted of Vehicle Code 23152(a) and VC 23152(b) VC, you will only be penalized once. The offenses "merge" for purposes of sentencing, which means that you are convicted of and sentenced for the DUI as one crime.26

California DUI expungement

If you were sentenced to probation after your VC 23152(a) DUI, and you successfully completed your probation, you can try to get your VC 23152(a) conviction expunged.

In order to receive a California DUI expungement, you and your DUI defense attorney will need to petition the court in which you were convicted. An expungement will eliminate the effects of the "driving under the influence" conviction for some purposes (like most job applications) but not others.

Call us for help...


If you or loved one is charged with Vehicle Code 23152(a) driving under the influence and you are looking to hire an attorney for representation, we invite you to contact us at Shouse Law Group. We can provide a free consultation in office or by phone. We have local offices in Los Angeles, the San Fernando Valley, Pasadena, Long Beach, Orange County, Ventura, San Bernardino, Rancho Cucamonga, Riverside, San Diego, Sacramento, Oakland, San Francisco, San Jose and throughout California.

Additionally, our Las Vegas Nevada DUI defense attorneys are available to answer any questions relating to Nevada's drunk driving laws. For more information, we invite you to contact our local attorneys at one of our Nevada law offices, located in Reno and Las Vegas.27

Additional Resources:

Online DUI Attorney Resources

Alcoholics Anonymous

Legal References:

  1. Vehicle Code 23152 California's Driving under the Influence Law. ("(a) It is unlawful for any person who is under the influence of any alcoholic beverage to drive a vehicle. (b) It is unlawful for any person who has 0.08 percent or more, by weight, of alcohol in his or her blood to drive a vehicle.") Most people arrested for DUI get charged with both crimes.
  2. Same.
  3. People v. Wilson (1985) 176 Cal.App.3d Supp. 1, 8. ("With regard to the offense of driving under the influence of an alcoholic beverage or drug (Vehicle Code 23152, subd. (a) [California's driving under the influence" law], a "slight movement" of the vehicle in the officer's presence has been a determinative factor in concluding whether or not a defendant was "driving" in the presence of the officer. ( Henslee v. DMV (1985) 168 Cal.App.3d 445, 450-453 [214 Cal.Rptr. 249]; see also People v. Engleman (1981) 116 Cal.App.3d Supp. 14, 18-20 [172 Cal.Rptr. 474].) In other words, a "slight movement" of the vehicle constitutes direct evidence that the vehicle was being "driven." (Cf. People v. Kelley, supra., 27 Cal.App.2d Supp. 771, 772-774.)...On the other hand, where the sufficiency of the evidence to support the judgment is in question, as contrasted with the validity of a defendant's arrest,FN4 it is clear that the existence of evidence establishing a "slight movement" of the vehicle does not present a problem.FN5 In the absence of such direct evidence of "driving", the element of "driving" may nonetheless be established at trial through circumstantial evidence...")
  4. Facts based on People v. Wilson, above.
  5. California Jury Instructions, Criminal. CALJIC 16.831 Alcohol or Drug Influenced Driving- Vehicle Code 23152(a) "Under the Influence"-Defined. ("A person is [under the influence of an alcoholic beverage] [under the influence of a drug] [under the combined influence of an alcoholic beverage and a drug] when as a result of [drinking such alcoholic beverage] [and] [using a drug] [his] [her] physical or mental abilities are impaired to such a degree that [he] [she] no longer has the ability to drive a vehicle with the caution characteristic of a sober person of ordinary prudence under the same or similar circumstances.")
  6. CALJIC 16.832 Alcoholic or Drug Influenced Driving under Vehicle Code 23152(a) California's Driving Under the Influence law. ("The manner in which a vehicle is being driven is not sufficient in itself to establish that the driver of the vehicle either is or is not [under the influence of an alcoholic beverage] [under the influence of a drug] [under the combined influence of an alcoholic beverage and a drug] [addicted to the use of a drug]. However, the manner in which the vehicle is being driven is a factor to be considered in light of all the proved surrounding circumstances in deciding whether the person operating the vehicle was or was not [under the influence of an alcoholic beverage] [under the influence of a drug] [under the combined influence of an alcoholic beverage and a drug] [addicted to the use of a drug].")
  7. CALJIC 12.61 Vehicle Code 23152(a) Driving Under the Influence-Inference of Intoxication. ("If the evidence establishes beyond a reasonable doubt that at the time of the chemical analysis of the defendant's blood, breath or urine, there was 0.08 percent or more by weight of alcohol in the defendant's blood, you may, but are not required to, infer that the defendant was under the influence of an alcoholic beverage at the time of the alleged offense.")
  8. CALJIC 16.831 Alcohol or Drug Influenced Driving-"Under the Influence"-Defined. ("[If it is established that a person is driving a vehicle [under the influence of an alcoholic beverage] [under the influence of a drug] [under the combined influence of an alcoholic beverage and a drug], it is no defense that there was some other cause which also tended to impair [his] [her] ability to drive with the required caution.]")
  9. See Terry v. Ohio (1968) 392 U.S. 1.
  10. Title 17 of the California Code of Regulations regulates all evidentiary procedures relating to California blood and breath testing in DUI cases.
  11. Police misconduct in a DUI case ranges from excessive force to perjury. 
  12. Ventura DUI defense attorney Darrell York uses his former experience as a Glendale Police Officer to represent clients accused of violating California's DUI laws at the Ventura Hall of Justice, the Van Nuys courthouse, the Pasadena courthouse, the Burbank courthouse, the Glendale courthouse, the Lancaster courthouse, the San Fernando courthouse, and the Criminal Courts Building.
  13. See Vehicle Code sections 23536 - 23548 for California DUI penalties for misdemeanor offenses.
  14. California DUI schools are regulated by Health and Safety Code sections 11836 et seq.
  15. License suspensions required for DUI cases are regulated by California Vehicle code sections 13350 et seq.
  16. California DMV DUI hearings must be requested within ten-days of your DUI arrest. For more information about DMV DUI hearings, please review our articles on DMV hearings.
  17. Canadian Immigration and Refugee Protection Act (“IRPA”) 36 [Canadian criminal inadmissibility, including for a DUI conviction].

    See also Canadian Criminal Code (“CC”) 253 [Canada's DUI law]. 

  18. California DUIs almost always have an effect on car insurance policies. For more information, please review our article on DUI and Car Insurance.
  19. Vehicle Code 23582 VC California's DUI speeding enhancement. 
  20. California Vehicle Code 23572 VC -- Minor in car; enhanced punishment [in a VC 23152(a) DUI case]. 
  21. Penal Code 273a California's child endangerment law [may be charged in addition to VC 23152(a) driving under the influence. 
  22. Vehicle Code 23103 per 23103.5 VC California's "wet reckless" law [potential plea bargain from Vehicle Code 23152(a) DUI].
  23. Vehicle Code 23103 VC California's "dry reckless" law [potential plea bargain from Vehicle Code 23152(a) DUI].
  24. Vehicle Code 23109(c) VC California's "exhibition of speed" law [potential plea bargain from Vehicle Code 23152(a) DUI].
  25. California Vehicle Code 23221 VC -- Drinking alcohol in a vehicle [potential plea bargain from Vehicle Code 23152(a) DUI].
  26. California Penal Code 654 -- Offenses punishable in different ways by different provisions; double jeopardy; denial of probation [applies to VC 23152(a) and 23152(b)]. 
  27. Please feel free to contact our Nevada criminal defense attorneys Michael Becker and Neil Shouse for any questions relating to Nevada's DUI laws. Their Nevada law offices are located in Reno and Las Vegas.




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