Being charged with DUI involving both alcohol and drugs can feel like the system is “stacking the deck” against you. And in many cases, prosecutors do treat combined-substance allegations more aggressively—because they can argue the substances amplified each other and increased impairment.
California’s “combined DUI” statute is Vehicle Code 23152(g). It generally targets drivers accused of being under the influence of alcohol and drugs at the same time. These cases are often built on a mix of subjective observations, field sobriety tests, DRE opinions, and chemical testing (breath and/or blood). The problem for the prosecution is that—just like drug DUI—much of this evidence can be challenged, and “a result on paper” does not automatically prove impairment at the time of driving.
And if your case involves injury, refusal, under-21 issues, or a child passenger, those require different strategies and higher-stakes planning.
What Is VC 23152(g) DUI (Alcohol + Drugs)?
Vehicle Code 23152(g) is commonly charged when law enforcement believes you were driving while impaired by a combination of alcohol and drugs. The “drug” in these cases can include marijuana/THC, prescription medication, over-the-counter medication, or an illegal substance. In practice, 23152(g) charges often show up when an officer claims there are signs of alcohol impairment and also points to indicators of drug use—such as admissions, an odor of cannabis, pills or paraphernalia, a DRE evaluation, or later blood results.
Many people are surprised to learn a 23152(g) charge may be filed even if your BAC is not extremely high, or even if you don’t feel “high,” the drug use happened earlier, or you took medication exactly as prescribed. That’s because the prosecution’s theory is often that the combination contributed to impairment, not that one substance alone necessarily crossed a clear threshold.
Combined DUI cases are highly fact-driven. A strong defense is built on what the evidence actually shows—video, timelines, testing methods, and documentation—not what it might suggest at first glance.
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.
Why Combined DUI Charges Are Treated More Seriously
Even when the baseline penalties may look similar on paper to a “standard” DUI, prosecutors often push harder in VC 23152(g) cases because they can argue the combination of alcohol and drugs creates greater impairment than either substance alone. They may also claim the driver’s condition was “unpredictable,” and use that framing to suggest the situation was more dangerous or reckless than a typical alcohol-only case.
That approach can affect how the case is handled from the beginning. It may influence charging decisions, the plea offers that are extended, and the probation terms the prosecutor seeks. It can also shape whether the state insists on specific conditions, such as testing requirements, particular programs, or additional restrictions like an IID, depending on the facts and the local court’s practices.
That’s why your defense needs to be organized and evidence-focused from the start—especially when the prosecution is trying to portray the case as “aggravated” based on allegations about combined impairment.
What the Prosecutor Must Prove
In simple terms, prosecutors usually try to prove three things in a VC 23152(g) case. First, they must show you drove a vehicle. Second, they must show that, at the time of driving, you were under the influence of alcohol and drugs. Third, they must show that the combined influence actually affected your ability to drive with the caution of a sober person using ordinary care.
The key idea is that the prosecution must prove impairment—not just the presence of alcohol or a substance in your system. This is where many defenses live, because blood tests can show some level of drug presence without proving impairment at the time of driving, and the rest of the case often depends on subjective police interpretation that may not hold up against video, timelines, and a careful review of the evidence.
Common Situations That Lead to 23152(g) Charges
VC 23152(g) charges often come up in everyday scenarios where an officer believes more than one substance may be involved, even if neither one seems extreme on its own. One of the most common situations is when a driver admits to having a drink and using marijuana earlier, or the officer claims to notice alcohol indicators—like odor, an admission, or a breath test result—along with cannabis cues such as an odor of marijuana, a statement about prior use, or items the officer associates with cannabis.
Another frequent scenario involves prescription medication combined with a small amount of alcohol. A driver may have taken medication as prescribed and then had one or two drinks, but the officer perceives drowsiness, slow responses, or confusion and assumes the driver was “mixing substances” in a way that created impairment. In other cases, a breath test result comes back under 0.08% and the officer then leans more heavily into a drug-impaired theory to justify an arrest, particularly when the officer expected a higher BAC based on their initial impressions.
Accidents and near-misses can also lead to 23152(g) charges because officers often look for impairment explanations quickly after a collision. The problem is that stress, injury, shock, and fatigue can mimic signs officers attribute to impairment, which can skew the interpretation of what they’re seeing. Finally, checkpoints are a common gateway to combined-DUI allegations: an officer may detect alcohol and then expand the investigation into drugs based on observations, questions, or admissions during the checkpoint contact.
Evidence in Alcohol + Drug DUI Cases
A VC 23152(g) case often pulls evidence from both the alcohol side and the drug side, which is part of what makes these cases feel more complex than an alcohol-only DUI. The file may include the reason for the stop and alleged driving pattern, along with officer observations about speech, coordination, eyes, and demeanor. It commonly includes field sobriety tests (FSTs) and some form of alcohol testing, such as a PAS test at the roadside or an evidentiary breath test at the station. On the drug side, blood testing is frequent and may include a drug panel and sometimes alcohol confirmation, and urine testing may appear as well—even though urine is generally less ideal for proving impairment at the time of driving. If a Drug Recognition Expert was involved, DRE evaluation notes can also become a key part of what the prosecution relies on.
Video and timing evidence often matter just as much as the tests. Bodycam and dashcam footage can confirm or contradict the officer’s narrative, and statements or admissions may be cited to support a “combined influence” theory. The timeline—driving to stop, stop to arrest, and arrest to testing—can be critical because it affects both alcohol evidence and drug evidence, especially when the prosecution must prove impairment at the time of driving rather than later.
Because a combined DUI is essentially “two lanes of proof,” it’s also two lanes of defense. One lane attacks the legal basis and procedure, including whether the stop, detention, investigation, and arrest were lawful and properly conducted. The other lane attacks the science and interpretation, including whether the testing is reliable and whether the state’s impairment conclusions actually follow from the evidence.
DRE Evaluations: What They Are and How We Challenge Them
In many combined DUI cases, law enforcement relies on a Drug Recognition Expert (DRE) to support the “drug impairment” portion of the allegation. The DRE evaluation is presented as a structured process, and it can include eye exams and pupil observations, divided-attention tasks, checks of vitals like pulse and blood pressure, and observations about muscle tone and overall behavior. At the end, the DRE often offers a subjective opinion about whether drug impairment is present and which drug categories may be involved.
Why DRE Opinions Can Be Vulnerable
Even when officers follow the steps, DRE opinions can still be challenged because many of the “signs” they rely on are not unique to drug impairment. Symptoms can overlap with fatigue, stress, illness, injury, or anxiety, and the testing environment itself is often unnatural and stressful—conditions that can affect performance and behavior. These cases also depend heavily on interpretation, which creates room for officers to treat ambiguity as impairment, especially when their written narrative doesn’t match what the video shows.
Another vulnerability is that DRE conclusions can be influenced by information learned during the investigation, such as admissions or later test results, which can create a risk that the evaluation becomes “reverse-engineered” to fit the theory. A strong defense focuses on whether the DRE conclusions are supported by objective facts—or whether they amount to an opinion built on assumptions.
Marijuana + Alcohol DUI: What Makes These Cases Different
When cannabis and alcohol are both alleged, prosecutors often argue the effects “stack,” meaning the combined influence created greater impairment than either substance alone. The defense, however, focuses on what the evidence actually proves—not what the combination might suggest in theory.
Common Issues in Marijuana + Alcohol Cases
A central problem in these cases is that THC presence does not automatically equal impairment at the time of driving. Lab results may detect THC metabolites that can linger and complicate interpretation, and those findings do not necessarily establish what—if anything—was affecting the driver during the actual driving. The investigation can also become biased once an officer believes “drugs are involved,” because claimed drug cues may color how the officer interprets speech, coordination, and even otherwise ordinary behavior. Field sobriety tests can add more noise than clarity, since performance can be influenced by many non-drug factors, and the timeline between use and driving is often critical to understanding what the test results really mean.
Practical Defense Approach
A strong defense in marijuana + alcohol cases typically starts with stop legality and whether the officer had a valid basis to initiate and expand the investigation. From there, video can be decisive—especially when it contradicts claims of impairment. The defense will often conduct a tight timeline analysis, comparing driving time to testing time, and highlight the scientific limits on drawing impairment conclusions from THC findings. Just as important, the defense may present alternative explanations for alleged symptoms, such as fatigue, anxiety, medical issues, or other non-impairment factors that can be mistaken for drug effects.
If marijuana is a key issue, also review: /practice/dui-dwi/drug-dui/
Prescription Medication + Alcohol DUI: Hidden Risk Scenarios
A major category of VC 23152(g) cases involves prescription medication combined with alcohol, even in small amounts. These cases often arise in “normal life” situations, such as taking a sleep medication the night before and having a drink the next day, taking anxiety medication and having a drink at dinner, or using pain medication and alcohol even when the driver doesn’t feel “high.” They can also involve stimulant medications paired with a drink, where normal energy, nervousness, or rapid speech is interpreted as “erratic” behavior rather than a benign explanation.
Defense Focus in Medication Cases
In medication-related combined DUI cases, the defense usually starts with the fundamentals: whether the stop was lawful and whether the arrest was supported by objective facts instead of assumptions. From there, the case often turns on whether the testing evidence actually proves impairment at the time of driving—or only shows the presence of a medication or alcohol after the fact. Video can be decisive as well, because bodycam and dashcam footage may support or contradict the officer’s narrative about speech, coordination, or behavior. Finally, medical context matters: fatigue, illness, vestibular issues, and other documented conditions can mimic “impairment” cues, and a careful defense highlights those explanations when the facts support them.
Medication DUIs often require careful, respectful handling because drivers may have legitimate medical conditions and lawful prescriptions. A strong DUI attorney builds the defense around evidence, timelines, and medical context—not assumptions about what a medication “must have” done.
DMV License Consequences and Deadlines
Depending on the facts, a VC 23152(g) arrest can trigger DMV action that puts your driving privileges at risk on a separate track from the court case. DMV-related consequences can move quickly, and the deadline to request a hearing may be short depending on the notice and paperwork you receive. Missing that window can mean losing the opportunity to challenge the suspension early.
This is why DUI defense is time-sensitive. It’s not just about what happens in court—it’s often about protecting your ability to keep driving while the case is pending, especially when work and family responsibilities depend on your license.
Breath Tests vs. Blood Tests in 23152(g) Cases
Breath Tests: Alcohol Tool, Not a Drug Tool
Breath testing is designed to estimate alcohol concentration, not drug impairment. It does not measure whether a person is impaired by THC, prescription medication, or any other drug. But in a VC 23152(g) case, a breath result is often treated as the “alcohol half” of the combined allegation, and prosecutors may pair that number with officer observations or drug-related claims to argue overall impairment.
Even so, breath tests are not beyond challenge. A defense may focus on whether required steps and observation periods were followed, whether the device’s maintenance and calibration history supports reliability, and whether the timeline creates “rising BAC” issues—especially when testing occurs well after driving. Medical conditions and physiological factors can also matter, because they may create false positives or distort results in ways that don’t reflect true BAC at the time of driving.
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Blood Tests: More Common for Drug Evidence
In a VC 23152(g) case, blood testing is typically used to look for drugs and can also be used to confirm alcohol concentration. Even so, a blood test is not automatically “bulletproof,” and the reliability of the result often depends on how the sample was collected, preserved, tested, and documented.
Common issues include chain-of-custody gaps that make it unclear who handled the sample, when, and under what conditions. Storage and handling problems can matter as well, because improper preservation or temperature control can affect sample integrity and increase the risk of degradation or contamination. Lab documentation and methodology are another frequent area of challenge—what procedure was used, whether it was followed, and whether the records are complete and consistent. Finally, interpretation is often disputed, especially on the drug side, because the presence of a substance does not automatically prove impairment at the time of driving.
Defenses That Work in 23152(g) Cases
A combined-substance case often creates multiple opportunities for reasonable doubt, because the prosecution is trying to stitch together two different theories—alcohol impairment and drug impairment—into one “combined influence” narrative. A strong defense is usually built around testing whether each link in that chain is lawful, reliable, and actually proves impairment at the time of driving.
Challenge the stop
If the stop was unlawful, key evidence gathered afterward may be challenged. In many cases, this is the first domino, because an invalid stop can undermine everything that follows, including field testing, statements, and chemical evidence.
Challenge probable cause to arrest
Even if the stop was valid, police still need a lawful basis to arrest for DUI. In combined cases, the arrest decision is sometimes driven by vague observations and assumptions rather than objective facts that clearly establish impairment. A defense focuses on whether the officer had real, articulable evidence—or whether the conclusion came first and the justification came later.
Use video to expose exaggeration
Bodycam and dashcam footage can be the best reality check in a 23152(g) case. Video may show whether your speech, balance, and coordination were actually impaired, and it can highlight inconsistencies between what happened and what the report claims. When the video doesn’t match the narrative, it can create powerful reasonable doubt.
Attack FST reliability
Field sobriety tests are not perfect and they’re not designed to diagnose specific substances. Performance can be affected by environment, fatigue, anxiety, injuries, footwear, uneven surfaces, or medical conditions that have nothing to do with impairment. A strong defense presses whether the tests were properly administered and whether the conclusions drawn from them are reliable.
Challenge breath testing
Breath testing is used to estimate alcohol concentration, but it can still be challenged on procedure, timing, and device reliability. The defense may also examine whether medical or physiological factors could have distorted the result and whether the timeline creates issues like a BAC that was rising after driving.
Related page: /practice/dui-dwi/breath-test-errors/
Challenge blood testing and lab documentation
Blood testing is often the centerpiece in 23152(g) cases, especially for the “drug” component of the allegation. Chain of custody, lab protocols, and documentation completeness can be critical, and interpretation is often disputed because presence does not necessarily mean impairment at the time of driving. A defense focuses on whether the blood evidence is reliable, properly handled, and actually supports the state’s theory.
Related page: /practice/dui-dwi/blood-test-errors/
Challenge DRE opinions
If the “drug half” of the allegation depends on a DRE opinion, the defense should scrutinize training, protocol compliance, documentation, and whether the conclusions logically match objective facts—particularly when video or other evidence contradicts the written narrative.
Alternative explanations for “impairment”
Fatigue, illness, anxiety, injury, and other medical conditions can mimic signs officers attribute to substance impairment. A strong defense highlights these alternative explanations when supported by the evidence, and presses whether the prosecution can truly rule them out beyond a reasonable doubt.
The goal is to show the prosecution cannot prove impairment beyond a reasonable doubt.
Penalties and What’s at Stake (Overview)
Penalties in a VC 23152(g) case depend on your prior record, the BAC allegations, the drug allegations, and whether any enhancements apply—such as an accident, an injury claim, an alleged refusal, or a child passenger. Even a first-time combined DUI can carry significant consequences, including probation terms, fines and penalty assessments, required programs, and driver’s license consequences that may begin quickly through the DMV process.
Because combined DUI cases can be more complex and more aggressively prosecuted, a meaningful analysis usually requires a close review of the full evidence—not just a summary of the charges. For a tailored assessment, a DUI defense lawyer should review the police report, video evidence, breath and blood documentation, and any DRE documentation if applicable, along with the full timeline of events. Local court practices also matter, because outcomes and standard terms can vary by county and courthouse.
What to Do After an Arrest for Drugs + Alcohol DUI
If your arrest is recent, acting quickly can protect both your defense and your driver’s license, especially if DMV action applies. Speaking with a DUI defense attorney early allows your lawyer to identify deadlines, preserve evidence, and shape the strategy before the state’s narrative hardens.
It also helps to write down your full timeline while it’s still fresh. That includes when you drank, when you used medication or cannabis, when you drove, when you were stopped, and when any breath, blood, or other tests occurred, because combined DUI cases often turn on timing and context. If medication is involved, preserve proof by keeping pharmacy records, prescription labels, and dosing instructions, since lawful use and dosage details can become important in understanding what the evidence does—and does not—prove.
Just as important, do not “explain” your case to anyone else. Statements can be misunderstood, repeated, or taken out of context, so it’s better to let your attorney guide what should and shouldn’t be said. Finally, gather medical context early if a condition could explain symptoms the officer attributed to impairment, because documentation created close in time to the arrest can be far more helpful than trying to reconstruct it later.
FAQs About VC 23152(g)
Is VC 23152(g) worse than a normal DUI?
It can be treated more seriously by prosecutors because they argue combined impairment, but each case depends on facts and proof.
If my BAC is under 0.08, can I still be charged?
Yes. A 23152(g) case is often framed as impairment-based. The defense then focuses on whether the evidence actually proves impairment.
Does a positive drug test automatically prove I was impaired?
Not automatically. Presence and impairment are not the same thing, and timelines and interpretation matter.
What if I used marijuana hours earlier and felt fine?
That’s a common scenario. The defense depends on the timeline, video, testing interpretation, and whether evidence proves impairment at the time of driving.