If you were arrested for DUI in Southern California, you’re probably dealing with stress, uncertainty, and a thousand questions all at once: Will I lose my license? Will I go to jail? What happens next? Can I beat this? The good news is that many DUI cases are defendable—especially when the stop was questionable, testing was flawed, procedures weren’t followed, or the evidence doesn’t actually prove impairment beyond a reasonable doubt.
This page focuses on the most common DUI charges in California—Vehicle Code 23152(a) and 23152(b)—often called a “standard” alcohol DUI. If your case involves drugs, injury, refusal, under-21 issues, or other enhancements, those deserve their own strategy and analysis. (We link to those pages throughout so you can go deeper.)
What Is a “Standard” DUI in California?
A “standard” DUI in California usually refers to an alcohol-based DUI charged under Vehicle Code 23152(a), Vehicle Code 23152(b), or both. VC 23152(a) is the impairment-based charge, where the state’s theory is that alcohol affected your ability to drive like a cautious, sober person. VC 23152(b) is the BAC-based charge, where the focus is on whether your blood alcohol concentration was 0.08% or higher.
These are the DUI charges most people think of after a traffic stop: an officer claims you showed signs of impairment, you were asked to perform field sobriety tests, and you took—or were asked to take—a breath or blood test. In general terms, California law makes it illegal to drive while under the influence, and it also makes it illegal to drive with a BAC of 0.08% or higher.
This page and website provide general information in plain English, not legal advice. Laws and local court/DMV practices vary and can change, so don’t rely on this content for your case—talk to a qualified attorney promptly to review your specific facts, especially if you face charges, a DMV action, or a deadline. In many cases, you’re fighting two battles at once: the DMV process and the criminal court case.
VC 23152(a) vs. VC 23152(b): What’s the Difference?
Impairment DUI: VC 23152(a)
Vehicle Code 23152(a) is the impairment-based DUI charge. The prosecutor’s theory is that alcohol affected your ability to drive like a cautious, sober person using ordinary care, and the case is often built on officer observations, driving pattern claims, and field sobriety test interpretation. The key point is that you can be charged under VC 23152(a) even if your BAC is under 0.08% if the state claims you were impaired. On the flip side, someone can look “fine” and still be charged if the officer’s report claims impairment, which is why video, timelines, and the details of the investigation often matter.
“Per Se” BAC DUI: VC 23152(b)
Vehicle Code 23152(b) is the “per se” BAC DUI charge. Instead of focusing on how you appeared, it focuses on your BAC number and whether the state can prove you were at 0.08% or higher at the time of driving. That “time of driving” issue matters because breath or blood testing usually happens after the driving, and delays can create timing questions that become central to the defense.
Both charges are commonly filed together, and a strong defense usually attacks both lanes: whether the officer had a valid basis to claim impairment under 23152(a), and whether the chemical test evidence is reliable and truly proves a 23152(b) BAC at the time of driving.
What the Prosecutor Must Prove
Every DUI case is ultimately about proof. The state has to prove the legal elements beyond a reasonable doubt, and those elements depend on which DUI theory is being charged.
For Vehicle Code 23152(a), prosecutors generally try to prove that you drove a vehicle and that, at the time of driving, you were under the influence of alcohol—in other words, impaired. For Vehicle Code 23152(b), prosecutors generally try to prove that you drove a vehicle and that, at the time of driving, your BAC was 0.08% or higher.
That “time of driving” issue is where many defenses live. Breath and blood tests are often taken after the driving, and because the body absorbs and processes alcohol over time, the testing number does not automatically answer what your BAC was when you were actually behind the wheel.
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Common Evidence in DUI Cases
DUI cases are usually built from two main categories of evidence: what the officer claims to have observed and what the testing evidence shows. The file often starts with the alleged reason for the stop—such as weaving, speeding, an equipment violation, or a checkpoint contact—and then moves into the officer’s observations about odor, red eyes, speech, balance, and overall demeanor. Many cases also include field sobriety tests like the walk-and-turn, one-leg stand, and HGN, along with a roadside PAS breath test that officers use during the investigation.
After an arrest, the evidence may expand to include an evidentiary breath test taken on a station breath device, blood test results with lab and chain-of-custody documentation, and bodycam or dashcam video that can confirm—or contradict—the written narrative. Time stamps also matter throughout, including driving time, stop time, arrest time, and test time, because timelines can raise issues about what the test results truly prove at the time of driving.
A DUI defense attorney’s job is to break down each piece of evidence and ask the questions that actually decide cases: Is it reliable? Is it legally admissible? And does it really prove the required elements beyond a reasonable doubt?
Two Cases at Once: DMV vs. Criminal Court
Most people assume a DUI is “one case.” In reality, you can end up fighting on two separate tracks at the same time: the DMV license action and the criminal court case, and they move on different timelines.
The DMV Side (Administrative Per Se / License Action)
If the DMV takes action against your license, you may have the right to request a hearing to challenge that suspension. The DMV states that hearings must be requested within 10 days of receiving notice (or 14 days from the date of the notice if it was mailed), and missing that deadline can mean losing the chance to fight the suspension through a hearing. That’s why DUI defense is time-sensitive—license consequences can hit fast, even before the court case is resolved.
Related pages: /practice/dui-dwi/dmv-hearing/ • /practice/dui-dwi/dui-license-suspension/
The Criminal Court Case
The criminal court case is where you fight the DUI charges and the risk of a conviction. A strong defense can lead to reduced charges, better terms, or—when appropriate—dismissal or a not-guilty result. Just as importantly, an organized defense plan helps ensure what happens in one track doesn’t unintentionally harm the other.
Related page: /practice/dui-dwi/dui-court-process/
DUI Defense Strategies That Can Make a Real Difference
There is no one-size-fits-all DUI defense. The best strategy comes from the facts, the timeline, and the evidence the state is actually relying on. But in many cases, DUI charges break down in a few recurring areas—where the legal foundation is weak, the investigation is flawed, or the testing evidence is less reliable than it looks on paper.
Traffic Stop Defenses
A DUI case often rises or falls with the legality of the stop. Police must have a lawful reason to pull you over, and the defense will often compare the officer’s stated reason to the video, the dispatch timeline, and what the driving actually shows. If the stop was based on an assumption rather than facts, or if the officer did not truly observe a Vehicle Code violation and is simply claiming one after the fact, that can become a major issue. When the stop is unlawful, your attorney may challenge the evidence that flowed from it.
Field Sobriety Test Challenges
Field sobriety tests are not perfect, and they’re heavily influenced by real-world variables. Anxiety, fatigue, stress, injuries, balance issues, age, uneven surfaces, poor lighting, and footwear can all affect performance. The defense also evaluates whether instructions were unclear or rushed and whether the officer’s scoring reflects bias or “confirmation” thinking. When conditions are poor or interpretation is overstated, the so-called “clues” can be misleading.
Related page: /practice/dui-dwi/field-sobriety-tests/
Breath Test Defenses
Breath testing can be challenged based on how the device was maintained, whether it was properly calibrated, and whether the operator followed required procedures. Timing and observation periods can matter, and physiological factors like mouth alcohol—burping, regurgitation, dental work, or residual alcohol—can distort results. Medical conditions such as GERD can also create issues in certain cases. A strong defense looks behind the number and tests whether the breath result is truly reliable.
Related page: /practice/dui-dwi/breath-test-errors/
Blood Test Defenses
Blood tests are not automatically “stronger,” and they can be challenged in multiple ways. Chain-of-custody issues can raise questions about who handled the sample and when. Storage and handling problems can affect integrity, and contamination or fermentation can distort results. Lab protocol and documentation errors can also undermine reliability, especially when the state’s interpretation goes beyond what the data can honestly support.
Related page: /practice/dui-dwi/blood-test-errors/
Rising BAC Defense
BAC changes over time. If testing happened long after driving, the central question becomes what your BAC was at the time you were actually driving—not what it was later at the station or hospital. Depending on the timeline, a “rising BAC” scenario can create reasonable doubt for a VC 23152(b) charge, especially when the prosecution assumes the test number automatically reflects BAC at driving time.
Related page: /practice/dui-dwi/rising-bac-defense/
Checkpoints and Enforcement Operations
If your case started at a checkpoint, the defense may focus on whether the checkpoint was conducted lawfully and consistently. Checkpoints involve constitutional and procedural requirements, and flaws in planning or execution can matter—especially when the stop and the expansion of the investigation were not handled properly.
Related page: /practice/dui-dwi/dui-checkpoints/
Potential Penalties for a First-Time DUI (Overview)
Penalties vary based on the facts, your record, and county practices, but a first-time DUI in California can still carry real sentencing exposure. Under Vehicle Code 23536, a first conviction of VC 23152 is punishable by county jail from 96 hours (with at least 48 continuous) up to six months, and a fine range of $390 to $1,000—before additional penalty assessments and fees that can significantly increase the total amount owed.
That’s why the goal of a DUI defense lawyer is not to “hope for the best.” It’s to attack the case where it’s weak and fight for the best achievable outcome—whether that means reduced charges when appropriate, minimized penalties, alternatives where available, protection of your license, and the best long-term result for your record and future.
Related page: /practice/dui-dwi/dui-penalties/
What to Do After a DUI Arrest
If your DUI is recent, the steps you take early can protect both your license and your defense. Start by speaking with a DUI lawyer immediately, because the early timeline matters—especially for DMV deadlines and preserving evidence before it disappears or gets overwritten.
You should also save every document you received and keep it in one place. That includes DMV paperwork, citations, release papers, and towing or impound information, because those documents often contain dates, deadlines, and details that shape the next steps. While your memory is fresh, write down your timeline in detail—where you were, what you ate or drank, when you drove, when you were stopped, what tests occurred, and what the officer said. In many cases, the outcome turns on timing and what was actually done and documented.
Avoid discussing the case with anyone other than your attorney. Statements can be used against you, even if they were meant to be harmless explanations. Finally, follow your attorney’s plan for both DMV and court. If a DMV hearing request is needed, it should be handled immediately—because DMV deadlines can be short and missing them can cost you important hearing rights.