Do I Have to Take a Breathalyzer in California?
It's one of the most common questions people have during a DUI stop — and one of the most misunderstood. The honest answer is: it depends which breath test you're talking about. California law treats the roadside handheld test very differently from the test given after an arrest, and confusing the two can cost you your license.
This post explains the difference in general terms. It is not legal advice — if you're dealing with a DUI, talk to an attorney about your specific situation.
There are actually two different breath tests
1. The roadside handheld test (the “PAS test”). During a traffic stop, an officer may ask you to blow into a small handheld device, called a Preliminary Alcohol Screening (PAS) test. For most drivers aged 21 and over who are not on DUI probation, this roadside test is generally optional. It's an investigative tool used to help establish probable cause to arrest — and declining it is, for many adults, allowed.
2. The test after arrest (the “chemical test”). Once you've been lawfully arrested for DUI, the situation changes completely. Under California's implied consent law, by driving on California roads you've agreed to submit to a chemical test — breath or blood — after a lawful DUI arrest. This is the test you generally cannot refuse without serious consequences.
Two big exceptions to the "optional" roadside test
The roadside PAS test is not optional if you are:
Under 21, or
On probation for a prior DUI.
In those cases, you're required to submit to the roadside test as well.
What happens if you refuse the post-arrest chemical test?
Refusing the required chemical test after a lawful arrest carries its own penalties, separate from the DUI charge itself. In general, a refusal can lead to:
An automatic license suspension — typically a year for a first refusal, and longer for subsequent ones,
Enhanced penalties if you're later convicted, and
The refusal being used as evidence against you in court.
In other words, refusing the post-arrest test doesn't make the DUI go away — it often makes things worse while adding a separate problem on top.
So what should you do?
There's no one-size-fits-all answer, and the smart roadside choices depend on the specifics. The general framework most people find useful: understand that the roadside handheld test is often optional for adults 21+ not on probation, while the post-arrest chemical test generally is not. Stay calm and polite either way. And if you've already been arrested, contact an attorney quickly — including about the 10-day deadline to protect your license through the DMV.
Frequently asked questions
Is the roadside breathalyzer the same as the one at the station? No. The roadside PAS device is a screening tool. The post-arrest breath (or blood) test is the evidentiary chemical test covered by implied consent.
Can I choose blood instead of breath? After a DUI arrest you can generally choose between a breath or blood test, though there are exceptions. An attorney can explain how this applied in your case.
I refused — is my case hopeless? No. A refusal raises the stakes, but it doesn't mean there's no defense. The circumstances of the stop, the arrest, and the refusal advisement all matter.
Questions about your DUI stop?
If you were arrested for DUI in Sonoma County and aren't sure whether your rights were respected, Chambers Defense can review what happened. Your consultation is free and confidential.
Call 415-849-7676 today.