California’s DUI law, codified in Vehicle Code section 23152, contains multiple subdivisions that create distinct bases for DUI prosecution. Most people are aware of the 0.08% BAC subdivision, but the law also prohibits driving under the influence of alcohol, driving under the influence of drugs, driving while addicted to a drug, and combinations thereof, each with its own elements and defenses.
Understanding the technical structure of these charges, and identifying which specific subdivision applies to your case and how to defend against it, requires legal expertise that goes far beyond general criminal defense knowledge.
The Multiple Subdivisions of Vehicle Code 23152
Vehicle Code 23152(a) prohibits driving under the influence of alcohol, a standard that is not simply defined by a BAC threshold but requires proof that the driver’s mental or physical abilities were impaired to the point that they could no longer drive with the caution characteristic of a sober person. A defendant with a BAC slightly above 0.08% might challenge the 23152(b) BAC offense while also defending against the 23152(a) impairment standard by presenting evidence of their actual driving performance, physical condition, and tolerance. Understanding how to mount simultaneous defenses under multiple subdivisions requires legal precision that only an experienced DUI Attorney Riverside can provide.
Vehicle Code 23152(f) and (g) address driving under the influence of drugs and the combination of alcohol and drugs. These charges are increasingly common as cannabis use has become legal and as prescription drug DUI cases have grown. They require specific proof of drug impairment, often through drug recognition expert testimony, which is itself subject to significant scientific criticism and legal challenge.
The Science of BAC Evidence and Its Vulnerabilities
Breath and blood test results are the evidentiary backbone of most DUI prosecutions, but both are subject to known scientific limitations and procedural vulnerabilities. Breath test devices measure alcohol in deep lung air and use a conversion ratio to estimate blood alcohol concentration. That conversion ratio is an approximation that varies among individuals, and certain physiological conditions, including elevated body temperature, hyperventilation, or GERD, can produce falsely elevated readings. Blood tests are more accurate but are subject to their own challenges, including improper storage, fermentation of the sample, and laboratory error.
A DUI Attorney Riverside who handles these cases regularly will know which specific vulnerabilities apply to the type of testing used in your case, will obtain the maintenance and calibration records for any breath device, will request the laboratory documentation for any blood test, and will work with forensic toxicology experts to evaluate the reliability of the results.
The Drug Recognition Expert: A Challenged Science
In cases prosecuted under the drug impairment subdivisions of Vehicle Code 23152, the prosecution often relies on the testimony of a drug recognition expert, or DRE, a law enforcement officer trained in a twelve-step protocol for identifying drug impairment. DRE testimony has been accepted in California courts but is also the subject of substantial scientific criticism. The DRE protocol has not been shown to reliably identify specific drugs or specific levels of impairment with the precision implied by its structured format.
An experienced DUI defense attorney will understand the specific scientific criticisms of DRE testimony, know which expert witnesses can effectively challenge it, and ensure that the jury has a full understanding of the limitations of this evidence before rendering a verdict.
When a Personal Experience Illustrated the Technical Stakes
I know someone personally who was charged under both 23152(a) and 23152(b) after a traffic stop in which his BAC was measured at 0.09% on a roadside preliminary alcohol screening device. He retained an experienced DUI Attorney Riverside who immediately identified that the PAS device used was a model with a known margin of error at the specific reading, that the officer had not complied with the required fifteen-minute observation period before administering the test, and that the defendant had consumed only a small amount of alcohol relative to his body weight and tolerance. The attorney retained a forensic toxicologist who testified about the margin of error in the PAS result and explained that the defendant’s actual BAC at the time of driving was likely at or below the legal limit. The jury acquitted on the BAC charge and deadlocked on the impairment charge, resulting in a mistrial. The prosecution eventually dismissed the case. Technical expertise was the entire basis for this outcome.
Your Defense Starts With the Right Attorney
A DUI charge under Vehicle Code 23152 is a serious legal matter with consequences that can affect every aspect of your personal and professional life. The right response is not resignation but vigorous, technically informed defense. An experienced DUI Attorney Riverside will evaluate every aspect of your case with the precision it requires, identify every viable defense, and pursue the best possible outcome with the knowledge and advocacy you deserve. Do not assume your case is unwinnable; consult a specialist and learn exactly where your defense stands.