If you are pulled over by law enforcement on suspicion of driving under the influence (DUI) in California, an officer may ask you to blow into a handheld device known as a Preliminary Alcohol Screening (PAS) test.
Officers frequently present this request as a mandatory command. However, under California law, most adult drivers have the legal right to refuse a PAS breath test before arrest.
Understanding when you can legally refuse—and when you must comply—is vital to protecting your driver's license and constitutional rights during a DUI stop.
What Is a PAS Breath Test?
A PAS breath test is a roadside screening tool used by police officers during DUI investigations to estimate a driver's blood alcohol concentration (BAC). It is legally categorized as part of the field sobriety testing process, much like walking a straight line or standing on one leg.
It is critical to distinguish the roadside PAS test from the post-arrest evidentiary chemical test administered at a police station or hospital. PAS devices are designed as quick indicators and are often more susceptible to calibration errors and environmental factors than post-arrest equipment.
Is the PAS Breath Test Mandatory in California?
For Most Drivers: No
If you are 21 years of age or older and not on DUI probation, you have the legal right to decline a roadside PAS breath test.
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Under these conditions, there are no automatic legal penalties for refusing a PAS test.
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Your refusal cannot be used by prosecutors as evidence of guilt at trial.
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Law enforcement officers are not legally required to tell you the test is voluntary, which often misleads drivers into complying.
When Is the PAS Test Mandatory?
California statutes carve out strict exceptions where refusing a PAS test carries immediate administrative penalties:
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Drivers Under 21 (Zero Tolerance Law): Under California's Zero Tolerance law, any driver under 21 who is pulled over on suspicion of DUI must submit to a PAS test upon request. Refusal results in an automatic one-year driver's license suspension by the DMV.
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Drivers on DUI Probation: Individuals currently serving a term of probation for a prior DUI conviction are legally required to submit to PAS testing when requested by an officer. Refusal triggers a probation violation and additional criminal penalties.
How the PAS Test Is Used by Law Enforcement
Police do not typically use roadside PAS results as direct trial evidence. Instead, officers rely on the numerical readout to establish probable cause to make a formal DUI arrest.
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If you take the PAS test and blow at or above the legal limit, the result justifies your immediate arrest and transport for chemical testing.
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If you lawfully refuse, the officer must rely entirely on independent evidence, such as your driving pattern, physical appearance (red eyes, slurred speech), and performance on standard field sobriety tests.
Why Drivers Frequently Decline a PAS Test
Criminal defense attorneys generally advise eligible drivers to decline roadside PAS testing for several technical reasons:
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Risk of False Positives: Mouth alcohol, specific medical conditions (like acid reflux or diabetes), diet choices, and improper device calibration can produce artificially elevated readings in sober individuals.
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Accuracy Concerns: Roadside conditions are rarely ideal, and PAS units can suffer from a margin of error of up to 15 percent.
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Creating Probable Cause: Agreeing to the test gives officers hard numerical data to justify an arrest they might not otherwise have.
What Happens After You Refuse a PAS Test?
Lawfully refusing a PAS test does not prevent an officer from arresting you if they believe other evidence establishes probable cause. However, once an officer makes a lawful arrest, California’s implied consent law takes effect.
Under California Vehicle Code Section 23612, any driver lawfully arrested for DUI must submit to a post-arrest chemical test (either breath or blood). Refusing this post-arrest test results in:
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Automatic driver's license suspension
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Enhanced mandatory jail time upon a subsequent DUI conviction
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Admissibility of the refusal in court as evidence of consciousness of guilt
Frequently Asked Questions (FAQs)
Can a police officer force me to take a PAS breath test at the roadside?
No. If you are 21 or older and not on DUI probation, you have the legal right to refuse. Officers may make the test sound mandatory, but it is voluntary prior to a formal arrest.
Can my refusal of a roadside PAS test be used against me in court?
Generally, no. For drivers over 21, a lawful refusal of a pre-arrest PAS test cannot be introduced as evidence of guilt or used to argue a consciousness of guilt during a criminal trial.
How is a PAS test different from the breathalyzer at the police station?
The PAS is a handheld, portable roadside screening device used to build probable cause before an arrest. The breathalyzer, or chemical test administered after arrest, is an evidentiary test subject to strict state regulations and calibration logs.
What if the officer never told me the PAS test was optional?
Police officers in California are under no legal obligation to inform drivers that a roadside PAS test is voluntary. Failure to advise you of your right to refuse does not automatically invalidate the stop, but an attorney can evaluate the context.
Will refusing a PAS test prevent my driver's license from being suspended?
Refusing a pre-arrest PAS test will not trigger a DMV suspension (assuming you are over 21 and not on probation). However, if you are subsequently arrested and refuse the mandatory post-arrest chemical test under implied consent laws, the DMV will initiate a suspension.
Facing a DUI investigation involving roadside breath testing or a chemical test refusal requires immediate legal intervention. Contact Cron, Israels & Stark in Los Angeles at 424-371-3112 for a confidential case evaluation.
