In California, driving under the influence (DUI) is a significant offense governed by specific state laws designed to address the dangers of operating a vehicle while impaired. One of the primary statutes prosecutors use is California Vehicle Code (CVC) 23152(a), which focuses on a driver’s impairment rather than a specific blood alcohol level.
Defining California’s Primary DUI Offense
California Vehicle Code section 23152(a) makes it illegal for a person who is “under the influence” of any alcoholic beverage to drive a vehicle.1California.Public.Law. California Vehicle Code Section 23152 (2025) The core of this law is not tied to a specific blood alcohol concentration (BAC), but on whether a person’s physical or mental abilities are impaired to the degree that they can no longer drive with the caution of a sober person.
The term “vehicle” is defined broadly and includes not just cars and trucks, but also motorcycles and scooters. “Driving” requires that the person has caused the vehicle to move, even a slight distance. The focus of this statute remains on the driver’s state of impairment, making it a subjective standard based on evidence of their condition and behavior.
Proving Driving Under the Influence of Alcohol
To secure a conviction, the prosecution must prove two elements: that the defendant was driving a vehicle and that, while driving, they were under the influence of alcohol. Prosecutors build their case using a combination of observations and tests. This includes the arresting officer’s testimony about the driver’s behavior, such as erratic driving patterns like swerving or braking.
Physical signs like red, watery eyes, slurred speech, or an unsteady gait are also presented as evidence. A driver’s performance on Field Sobriety Tests (FSTs) is another piece of evidence used to demonstrate impairment. While a chemical test showing a driver’s BAC can be used to support the charge, it is the collection of all circumstantial evidence that is used to prove the driver was impaired.
Penalties for an Alcohol-Related DUI Conviction
A first-time misdemeanor conviction for this offense carries a range of penalties. These consequences include a period of informal probation lasting from three to five years. Fines are also a standard penalty, with base fines ranging from $390 to $1,000, though total costs can be much higher after court assessments and fees are added.
Convicted individuals are required to complete a mandatory DUI education program, with a length of three or nine months depending on the case. A conviction also results in a driver’s license suspension imposed by the court, which can last from six to ten months. The Department of Motor Vehicles (DMV) will also take separate administrative action against the person’s driving privilege, a proceeding independent of the criminal court case. Penalties become progressively more severe for second or subsequent offenses within a ten-year period.
Factors That Can Increase DUI Penalties
Penalties for a conviction can be substantially increased if certain aggravating factors are present. These factors include:
- Having a passenger under the age of 14 in the vehicle at the time of the offense, which adds a mandatory 48 hours of jail time to a first-time DUI sentence.
- Driving recklessly in addition to speeding. This enhancement applies if the person was driving 30 mph or more over the speed limit on a freeway or 20 mph or more over the limit on any other street, resulting in a mandatory 60-day jail sentence.
- Having a particularly high BAC, often 0.15% or greater.
- Causing an accident that results in property damage or injury to another person.
- Refusing to submit to a chemical test after a lawful arrest. This action carries its own separate penalties, including a longer license suspension, and is also considered an aggravating factor by the court during sentencing.
The “Impairment” DUI Charge Compared to the “.08 BAC” Charge
In California, it is common for a driver to be charged with violating both the impairment statute and CVC 23152(b), the “.08 BAC” or “per se” charge. The difference lies in what the prosecution must prove. For the impairment charge, the focus is on whether the driver’s abilities were actually impaired by alcohol, regardless of their specific BAC. In contrast, the per se charge makes it illegal to drive with a BAC of 0.08% or higher, and a conviction can be based on that chemical test result alone.2Justia. CALCRIM No. 2111. Driving With 0.08 Percent Blood Alcohol (Veh. Code, § 23152(b)) :: California Criminal Jury Instructions (CALCRIM) (2025)
This dual-charge strategy gives the prosecution two different avenues to secure a DUI conviction. A person can be found guilty of either or both offenses based on the same incident. However, the law prevents punishment for more than one of the offenses, as they arise from a single act of driving.3FindLaw. California Code, Penal Code – PEN § 654 This distinction allows for prosecution even when a driver’s BAC is below 0.08% if there is still clear evidence of impairment.