If you are pulled over for suspected DUI in California, a police officer may ask you to blow into a handheld breath device known as a Preliminary Alcohol Screening (PAS) test.
Officers often present this request as mandatory, but in most situations, adult drivers have the legal right to refuse a PAS breath test before arrest.
Understanding when you can legally refuse — and when you cannot — is critical to protecting your rights in a DUI investigation.
What Is a PAS Breath Test?
A PAS breath test is a handheld roadside device used by police officers during DUI investigations to estimate a driver's blood alcohol concentration (BAC). It is administered before an arrest and is considered part of the field sobriety testing process, similar to walking a straight line or standing on one leg.
The PAS test is not the same as the evidentiary breath test administered after arrest at a police station or jail. PAS devices are designed as screening tools and are often less accurate than post-arrest chemical testing equipment.
Is the PAS Breath Test Mandatory in California?
For Most Drivers: No
If you are:
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21 years of age or older, and
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Not on DUI probation,
You may legally refuse a PAS breath test before you are arrested. There is no automatic penalty for refusal, and refusal cannot be used as evidence of guilt at trial.
Police officers are not required to inform you that the PAS test is optional, which often leads drivers to believe refusal is illegal when it is not.
When Is the PAS Test Mandatory?
California law provides two important exceptions where refusal is not allowed:
1. Drivers Under 21 (Zero Tolerance Law)
Under California's Zero Tolerance DUI laws, drivers under the age of 21 must submit to a PAS test when requested. Refusal can result in:
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An automatic driver's license suspension, and
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Administrative penalties through the DMV.
2. Drivers on DUI Probation
Drivers currently on probation for a prior DUI conviction must submit to PAS testing when requested by law enforcement. Refusal may lead to:
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A probation violation, and
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Additional criminal penalties.
How the PAS Test Is Used by Police
The PAS breath test is not typically used as direct evidence of guilt at trial. Instead, officers rely on it to establish probable cause to arrest a driver for DUI.
If you agree to take the PAS test and it shows a BAC at or above the legal limit, the result can be used to justify your arrest and further testing. If you refuse, the officer must rely on other evidence, such as:
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Driving pattern,
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Field sobriety test performance,
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Physical observations (odor of alcohol, slurred speech), or
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Statements made during the stop.
Reasons Drivers Often Decline a PAS Test
There are several reasons why criminal defense attorneys often advise eligible drivers to decline a PAS test:
Risk of False Positives
Even sober drivers may register a positive reading due to:
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Mouth alcohol,
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Medical conditions,
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Certain foods or medications, or
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Device calibration errors.
Accuracy Concerns
PAS devices can have a margin of error of up to 15 percent, and roadside testing conditions are rarely ideal.
Probable Cause Creation
Taking the PAS test gives police additional evidence to justify an arrest. Without it, officers must rely more heavily on subjective observations, which may later be challenged in court.
What Happens If You Refuse a PAS Breath Test?
If you lawfully refuse a PAS test:
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You cannot be penalized solely for refusing, and
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The refusal cannot be used against you at trial (for most adult drivers).
However, refusal does not prevent arrest. If the officer believes probable cause exists based on other factors, you may still be arrested. Once arrested, California's implied consent law applies.
Implied Consent After Arrest
Under California Vehicle Code 23612, drivers who are lawfully arrested for DUI must submit to a chemical test — breath or blood — after arrest.
Refusing a post-arrest chemical test can result in:
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Automatic license suspension,
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Use of refusal evidence against you in court.
This is entirely separate from the optional PAS test conducted before arrest.
Can PAS Refusal Be Used Against You in Court?
Generally:
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Before arrest: PAS refusal is not admissible as evidence of guilt (unless you fall under an exception).
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After arrest: Refusal of a required chemical test can be used against you.
Prosecutors sometimes attempt to argue “consciousness of guilt,” but courts carefully scrutinize such claims when the refusal was legally permitted.
How to Refuse a PAS Test Politely
If you decide to refuse:
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Remain calm and respectful,
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Do not argue with the officer,
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State clearly: “I respectfully decline the PAS test.”
Avoid making additional statements or engaging in confrontational behavior, which can complicate your situation.
Why Legal Advice Matters in PAS Refusal Cases
DUI investigations are technical, and mistakes made during roadside testing can have serious consequences. Whether refusing or submitting to a PAS test was the right choice depends on the facts of your case.
An experienced DUI defense attorney can review:
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Whether your refusal was lawful,
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Whether the arrest was supported by probable cause, and
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Whether the evidence obtained should be suppressed.
Contact a California DUI Defense Attorney
If you were stopped for DUI, refused a PAS breath test, or were arrested following roadside testing, your rights and driving privileges may be at risk.
Contact Cron, Israels & Stark for a confidential case evaluation. Our firm represents clients throughout California, including Los Angeles County, in DUI and serious criminal defense matters.
