Vehicle Code 23152 – Challenging Breathalyzer Results
Under California Vehicle Code 23152, it is unlawful to drive under the influence of alcohol. A driver with a blood alcohol concentration (BAC) of 0.08 percent or higher is presumed to be driving under the influence.
A DUI conviction in California can result in:
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Fines and court assessments
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Informal probation
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DUI education programs
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License suspension
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Jail time
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Increased insurance rates
In Los Angeles County, thousands of DUI cases are filed every year. In most of these cases, the prosecution's primary evidence is the breath test result.
However, breathalyzer results are not automatically accurate or unbeatable.
What Is a DUI Breath Test?
After a traffic stop, officers may:
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Request a preliminary alcohol screening (PAS) test
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Arrest you on suspicion of DUI
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Administer an evidentiary breath test at the station
The breathalyzer estimates your BAC by analyzing alcohol content in your breath and applying a conversion ratio to approximate blood alcohol levels.
If your BAC is 0.08 percent or higher, prosecutors will typically file DUI charges.
However, a breath test reading above 0.08 does not guarantee conviction.
Why Breathalyzer Results Can Be Challenged
Breath test evidence is often the foundation of a DUI case, but it is not infallible.
Potential weaknesses include:
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Machine error rates
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Calibration problems
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Improper administration
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Rising blood alcohol levels
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Medical conditions
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Mouth alcohol contamination
An experienced DUI defense attorney can examine these factors in detail.
Showing That Breathalyzers Are Not Always Reliable
Breath testing devices have documented error margins. In borderline cases — such as 0.08 or 0.09 percent — even a small margin of error may create reasonable doubt.
Defense strategies may include:
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Challenging the machine's maintenance records
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Reviewing calibration logs
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Examining operator certification
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Cross-examining forensic experts
Scientific research has shown that breath testing devices rely on assumptions that may not apply equally to every person.
The Timing of the Breath Test
One of the most important issues in DUI defense is timing.
The legal question is not what your BAC was at the station.
The question is what your BAC was at the time you were driving.
Alcohol absorption continues after you stop drinking. In some cases, a person's BAC may have been below 0.08 while driving but rose above 0.08 by the time testing occurred.
This is known as the “rising blood alcohol” defense.
If significant time passed between driving and testing, the prosecution may struggle to prove your BAC at the time of driving beyond a reasonable doubt.
Improper Administration of the Breath Test
Breath tests must be administered according to strict procedures.
Officers are required to:
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Observe you for a continuous 15-minute period before testing
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Ensure you do not burp, vomit, eat, or drink
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Follow standardized operational steps
Failure to follow protocol can invalidate results.
Additionally, the officer must be properly trained and certified to operate the machine.
Medical Conditions That Affect Breath Tests
Certain medical issues can artificially inflate BAC readings.
Examples include:
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Acid reflux or GERD
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Diabetes
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Ketogenic dieting
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Dental work or mouth alcohol residue
Because breathalyzers measure breath alcohol rather than direct blood alcohol, contamination can occur.
Illegal Traffic Stop or Illegal Search
Police must have reasonable suspicion to initiate a traffic stop.
If the stop lacked legal justification, any evidence obtained — including breath test results — may be suppressed.
Additionally, although California is an implied consent state, constitutional protections still apply.
If the arrest was unlawful, the breath test may be excluded.
Implied Consent in California
California’s implied consent law means:
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By driving, you agree to submit to chemical testing after lawful arrest
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Refusal can result in automatic license suspension
However, the officer must first make a lawful arrest.
If procedures were not followed, administrative penalties may be challenged.
Frequently Asked Questions
Can you beat a DUI with a breath test over 0.08?
Yes. Breath tests can be challenged based on machine error, rising BAC, improper administration, or constitutional violations.
Are breathalyzers always accurate?
No. Breath testing devices have error margins and rely on assumptions that may not apply to every individual.
What if my BAC was close to 0.08?
Borderline cases often provide stronger opportunities for negotiation or dismissal due to margin of error arguments.
Can medical conditions affect breath results?
Yes. GERD, diabetes, and other conditions can affect readings.
What happens if I refuse a breath test?
Under implied consent laws, refusal can lead to license suspension. However, the legality of the stop and arrest can still be challenged.
Los Angeles DUI Defense Attorneys
DUI breath test cases require careful technical and legal analysis. Prosecutors rely heavily on chemical test results, but those results are not immune from challenge.
Cron, Israels & Stark represents clients throughout Los Angeles and Southern California in DUI matters.
Our attorneys:
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Review breath machine maintenance logs
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Analyze bodycam and dashcam footage
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Consult forensic toxicology experts
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Challenge unlawful stops
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Defend DMV license suspension hearings
If you have been arrested for DUI under Vehicle Code 23152, contact our office for a confidential case evaluation.
Early intervention can significantly impact both your court case and your driver's license.
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