California has various laws that govern driving under the influence. These laws are outlined under California Vehicle Code, and they govern offenses related to driving with a BAC exceeding the legal limit, driving while under the influence of alcohol, driving under the influence of drugs, underage driving, and other drunk-driving-related offenses.

The state has continuously been changing DUI laws as prosecutors push for the harshest possible punishments to curb drunk driving. However, this doesn’t mean you are guilty once accused of a DUI offense. You have to fight the charges leveled against you to have the possible punishments reduced or even have the charges dropped altogether.

Because of the complex nature of California DUI laws, you should consider having representation from an attorney who is conversant with DUI laws and DUI defense. This would possibly make a difference between imprisonment/jail term and freedom. If you are in the Chula Vista area, we invite you to contact us at Chula Vista Criminal Attorney for DUI defense services.

DUI Under Vehicle Code 23152(a)

Under Vehicle Code 23152(a), DUI (Driving Under the Influence) is defined as operating a motor vehicle while being "under the influence" of alcohol or drugs. The phrase "under the influence" refers to a state where a person's physical or mental abilities are impaired to a degree that they can no longer drive with the caution and care of a sober individual.

It's important to note that "under the influence" does not solely rely on the driver's blood alcohol concentration (BAC) level. While a BAC of 0.08% or higher is considered a per se violation of the law, meaning it establishes a DUI offense regardless of impairment, Vehicle Code 23152(a) recognizes that impairment can exist even at lower BAC levels or without exceeding the legal limit.

The term "under the influence" encompasses various factors that may contribute to impairment, including the effects of alcohol or drugs on an individual's cognitive, physical, and psychomotor functions. These effects can include impaired judgment, diminished reaction time, reduced coordination, altered perception, and impaired concentration, all of which can significantly impact a person's ability to safely operate a motor vehicle.

A law enforcement officer may determine whether a driver is "under the influence" through various means, such as observations of driving behavior, field sobriety tests, physical appearance, an odor of drugs or alcohol, and other objective indicators of impairment.

DUI cases involving drugs (DUID) follow a similar principle, where impairment from drugs, whether prescription, over-the-counter, or illicit substances, can lead to a DUI offense under Vehicle Code 23152(f). In drug-related DUI cases, determining impairment may involve evaluations by drug recognition experts or toxicology reports.

Law enforcement officers must have probable cause to make a DUI arrest. Here are three common field sobriety tests (FSTs)for impairment that can lead to a DUI arrest:

  1. One-Leg Stand (OLS) — This test evaluates a driver's balance, coordination, and ability to follow instructions. In this test, the driver is instructed to raise one foot approximately six inches off the ground while counting aloud. The officer looks for signs of impairment, like hopping or swaying to maintain balance, using arms for balance, or inability to maintain the raised foot for the required duration.
  2. Walk and Turn (WAT) — The Walk and Turn test assesses both physical coordination and mental processing. The driver is asked to take nine heel-to-toe steps along a straight line, pivot, and return in the same manner. During this test, the officer looks for signs of impairment, including difficulty maintaining balance, inability to walk heel-to-toe, using arms for balance, improper turning, or stepping off the line.
  3. Horizontal Gaze Nystagmus (HGN) — The HGN test assesses the involuntary jerking of the eyes that occurs when a person gazes to the side. Alcohol and certain drugs can exaggerate this jerking, known as nystagmus. During the test, an officer will ask the driver to follow a moving object, such as a pen or flashlight, with their eyes while keeping their head still. The officer observes the eyes for any distinct nystagmus indicators, such as onset before reaching a 45-degree angle or lack of smooth pursuit.

FSTs are subjective and can be affected by various factors, such as pre-existing physical conditions, fatigue, nervousness, or environmental factors. Additionally, officers may employ additional non-standardized tests, such as the finger-to-nose test or alphabet recitation, to gather further evidence of impairment.

If an officer believes a driver has failed field sobriety tests or exhibits other signs of impairment, they may proceed with a breathalyzer test, blood test, or urine test to measure the driver's blood alcohol concentration (BAC) or detect the presence of drugs.

California Standard DUI (Per Se) Law

The DUI per se law (Vehicle Code 23152(b)) is an important aspect of DUI legislation. The per se law establishes that individuals can be charged with a DUI offense solely based on their blood alcohol concentration (BAC) level, regardless of whether they show signs of impairment while operating a motor vehicle.

Under the per se law, if a person's BAC is found to be at or above the legal limit of 0.08% for adult drivers, they can be charged with a DUI offense, even if they exhibit no obvious signs of impairment. This means that the BAC test results alone can serve as evidence of a DUI violation.

Note that the per se law applies to alcohol-related DUI cases. In cases involving driving under the influence of drugs (DUID), California has separate laws and procedures that determine impairment, as there is no established legal limit for drug impairment comparable to the BAC limit for alcohol.

The per se law simplifies the process of prosecuting DUI cases by focusing on measurable BAC levels rather than relying solely on subjective observations of impairment. It allows law enforcement officers to make arrests and file charges based on scientific evidence obtained through breath, blood, or urine tests.

Understanding BAC and How to Challenge the BAC Results

Blood Alcohol Content (BAC) is a measure of the amount of alcohol in a person's bloodstream, expressed as a percentage. It indicates the level of alcohol impairment and is commonly used to determine DUI offenses.

Various factors can impact BAC levels. Such factors include the number of drinks consumed, the rate of alcohol metabolism, body weight, gender, and individual tolerance.

While BAC tests are considered scientific evidence, they are not infallible, and there are potential defenses that can be raised to challenge their accuracy or reliability:

  • Testing equipment calibration — Breathalyzer devices or blood testing equipment must be properly calibrated and maintained. Failure to adhere to calibration standards or using faulty equipment can cast doubt on the accuracy of the results.
  • Testing procedure errors — Law enforcement officers must follow specific protocols when administering BAC tests. Any deviations from these protocols, such as improper handling of the testing equipment or failure to observe the required waiting period before administering the test, can impact the reliability of the results.
  • Medical conditions or interference — Some medical conditions or substances can affect BAC results. Conditions such as acid reflux, diabetes, or the presence of mouth alcohol can potentially result in falsely elevated BAC readings. Additionally, substances like mouthwash, breath fresheners, or certain medications may interfere with the accuracy of breathalyzer tests.
  • Rising BAC — The "rising BAC" defense argues that a person's BAC was below the legal limit while driving but increased above the limit by the time the test was administered. This defense relies on the fact that alcohol absorption can continue for a period of time after a person stops drinking.

In some cases, it may be beneficial to present testimony from experts in forensic toxicology. These experts can provide insights into potential errors in the testing process, equipment reliability, or the impact of medical conditions on BAC results.

Implied Consent Law

Under this law, by choosing to drive in California, drivers are deemed to have given their implied consent to submit to chemical testing if lawfully arrested on suspicion of driving under the influence (DUI).

Here are key points regarding California's implied consent law:

  • Testing methods — The implied consent law allows law enforcement officers to request chemical tests to determine the driver's blood alcohol concentration (BAC) or the presence of drugs in their system. The tests typically include breathalyzer (breath) tests, blood tests, or urine tests.
  • Consequences of refusal — If a driver refuses to submit to a chemical test, they can face additional penalties, regardless of whether they are ultimately found guilty of a DUI offense. Refusal to comply with testing can result in a longer driver's license suspension and other administrative consequences, as determined by the California Department of Motor Vehicles (DMV).
  • Information provided — Before conducting the chemical test, law enforcement officers are required to inform the driver of the consequences of refusal, including the potential license suspension and the use of the refusal as evidence in court.
  • Test options — In most cases, drivers are given the choice between a breath test or a blood test. However, if the officer suspects drug impairment, they may request a blood or urine test.
  • Admissibility in court — Refusal to submit to a chemical test can be presented as evidence against the driver in court. The prosecution may argue that the refusal indicates consciousness of guilt or an attempt to conceal the presence of alcohol or drugs.

Misdemeanor Punishments for 1st, 2nd, & 3rd DUIs Under Vehicle Code 23152

California DUIs are usually charged as misdemeanors. Misdemeanor DUI offenses must meet these conditions:

  1. It is the first, second, third, or wet reckless offense within 10 years.
  2. Nobody was injured.
  3. You have no prior conviction for felony DUI.

Here are punishment for misdemeanor 1st, 2nd, and 3rd DUIs:

Jail Term

  • Up to 6 months for 1st offense DUI.
  • 96 hours to one year for 2nd offense DUI.
  • 120 days to one year for 3rd offense DUI.


Fines range from $390 to $1,000 for misdemeanor DUI offenses.

Summary/Misdemeanor Probation

Probation length ranges from 3 to 5 years.

DUI School

  • 3 or 9 months for first-time offenders.
  • 18 or 30 months for second-time offenders.
  • 30 months for third-time offenders.

DMV License Suspension

  • 4 months for first-time offenders. Alternatively, you can have an ignition interlock device (IID) installed in your vehicle for 6 months, or request a restricted license after 30 days. A restricted license allows you to drive to and from work for five months.
  • Two years for second-time offenders. Alternatively, you can have an IID for one year.
  • Three years for third-time offenders or a mandatory IID installation for a period of two years. The Department of Motor Vehicles (DMV) will also designate you a Habitual Traffic Offender.

These penalties are similar for commercial drivers, but commercial drivers' legal limit is lower (0.04%) and can lead to the loss of a Commercial Driver’s License (VEH 23152(d).

Driving Under the Influence of Drugs Under Vehicle Code 23152 (f)

Driving under the influence of drugs refers to operating a motor vehicle while impaired by any drug or a combination of drugs and alcohol. The impairment must be to the extent that it affects the driver's ability to operate the vehicle safely.

The term "drug" in this context encompasses both illegal drugs and prescription or over-the-counter medications that can impair a person's ability to drive. It includes substances such as marijuana, cocaine, methamphetamine, opioids, hallucinogens, and other controlled substances.

Law enforcement officers may employ various methods to determine drug impairment during a traffic stop, such as observing physical symptoms, conducting field sobriety tests, or requesting a drug recognition expert (DRE) evaluation. Additionally, chemical tests, such as blood or urine tests, can be used to detect the presence of drugs in the driver's system.

The penalties for a DUID conviction under VC 23152(f) are similar to those for alcohol-related DUI offenses.

California Zero-Tolerance (Underage Drinking and Driving) Law Under VC 23136

The zero-tolerance law, also known as the underage drinking and driving law, pertains to the prohibition of individuals under the legal drinking age from operating a motor vehicle with any measurable amount of alcohol in their system. It is designed to discourage underage drinking and promote safe driving practices.

The zero-tolerance law establishes that individuals under the age of 21 must not have a blood alcohol concentration (BAC) level of 0.01% or higher while driving. It sets a stricter standard compared to the general DUI law for adults, where a BAC level of 0.08% or higher is considered illegal.

A violation of this law is not a criminal offense; it is a civil offense. Therefore, violating the zero-tolerance law can only result in administrative penalties, primarily imposed by the state's Department of Motor Vehicles (DMV). The penalty involves the suspension of the driver's license (or delay of getting one if you do not have a driver’s license) for one year.

California law discourages a conviction for two crimes for one offender. But this can be different if you violate the zero-tolerance law; in this case, you might face an additional DUI charge, such as underage DUI under VEH 23140), specifically if your BAC is close to 0.05%. This notwithstanding, you can only be convicted of one crime.

California Underage DUI Law Under Vehicle Code 23140

Under Vehicle Code Section 23140 in California, underage DUI (Driving Under the Influence) refers to the offense committed by individuals under the age of 21 who operate a motor vehicle with a blood alcohol concentration (BAC) level exceeding 0.05%. This particular code section addresses DUI offenses specific to drivers who are not of legal drinking age.

This offense is usually an infraction, with the following penalties:

  • Driver’s license suspension for one year.
  • $100 in fines.
  • 3 or more months of mandatory alcohol education program for drivers above 18.

An underage driver who operates a vehicle with a BAC exceeding 0.08% will be charged under the standard DUI law (Vehicle Code 23152). This carries the following punishments:

  • Up to six months in jail. This is usually rare.
  • $390 to $1,000 in fines.
  • Informal probation of 3 to 5 years.
  • DUI school of 3 months or 9 months.
  • License suspension period of one year.

An underage DUI might also be charged under the following laws:

  • Driving under the influence of drugs (VEH 23152(f)).
  • DUI causing injury (VEH 23153).
  • Watson murder/ DUI murder (PEN 187).
  • Vehicular manslaughter while intoxicated (PEN 191.5).

Note that underage drivers cannot refuse to submit to a preliminary alcohol screening or an evidentiary BAC test. Otherwise, their license might be revoked for two years or have a minimum license suspension of one year, in addition to enhanced penalties.

DUI Causing Injury Under Vehicle Code 23153

DUI causing injury, as defined by Vehicle Code 23153, occurs when a person operates a motor vehicle under the influence of alcohol or drugs and, as a result of that intoxication, causes bodily injury to another person.

Bodily injury refers to any physical harm or impairment suffered by another person. It can range from minor injuries, such as bruises or cuts, to more severe injuries, including broken bones, concussions, or internal injuries.

To establish the offense of DUI causing injury, the prosecution needs to prove the following elements beyond a reasonable doubt:

  • The defendant was driving a motor vehicle.
  • The defendant was under the influence of alcohol or drugs while driving.
  • The defendant's intoxication caused bodily injury to another person.

DUI causing injury is considered a "wobbler" offense in California, meaning it can be charged as either a misdemeanor or a felony, depending on the circumstances of the case. The specific penalties depend on factors such as prior DUI convictions, the extent of the injuries, and other aggravating factors.

For a misdemeanor DUI causing injury, potential penalties may include:

  • Up to one year in county jail.
  • Up to $5,000 in fines.
  • 3 to 5 years of informal probation.
  • Up to 3 years license suspension.
  • Restitution to injured victims.
  • Completion of DUI school.

For a felony DUI causing injury, the penalties can be more severe and may include:

  • Up to 4 years in state prison.
  • Up to $5,000 in fines.
  • Habitual Traffic Offender status for 3 years.
  • A “strike” on your record.
  • Driver’s license revocation for five years.

DUI With a Minor Under 14 (Vehicle Code 23572)

DUI with a minor, as defined by Vehicle Code 23572, occurs when a person operates a motor vehicle while under the influence of alcohol or drugs and has a passenger who is under the age of 14 in the vehicle.

This law is closely related to child endangerment law under Penal Code 273(a). As a result, it carries harsher penalties than regular DUI charges.

If you are convicted of this offense, you will penalties of a regular DUI offense, with the following additional jail term:

  • 48 hours for first-time offenders.
  • 10 days for second-time offenders.
  • 30 days for third-time offenders.
  • 90 days for fourth-time offenders.

Felony DUI Law

A California felony DUI occurs when:

  1. You have a prior conviction of felony DUI.
  2. You have three DUI priors within 10 years, meaning this is your fourth DUI charge. Prior convictions include California DUI, wet reckless, or an out-of-state conviction that is equivalent to a California DUI, or
  3. Your action causes serious bodily injury or death.

California DUI carries harsher penalties than standard misdemeanor DUI, and can be prosecuted under:

  1. DUI causing serious injury law (VEH 23513).
  2. Watson murder law.
  3. Vehicular manslaughter while intoxicated (PEN 191.5(b)), or
  4. Gross vehicular manslaughter while intoxicated (PEN 191.5(a)).

Find a DUI Defense Attorney Near Me

DUI laws are ever-evolving, and law enforcement officers are increasingly devising ways to arrest drivers suspected of DUI. Once you are charged, the prosecutor will likely push for the harshest possible penalties. Due to the intricate nature of California DUI laws, you shouldn’t face your charges alone; a knowledgeable defense attorney can help fight the charges leveled against you.

We at Chula Vista Criminal Attorney are ready to help defend you if you are facing DUI charges in Chula Vista. Contact us at 619-877-6894 to learn more about how we can help you.