It depends on when the test is offered. There are two different breath tests, and the rules are not the same for each.
Before an arrest, at the roadside, officers often ask you to blow into a handheld preliminary alcohol screening (PAS) device. For most adults over 21 who are not on DUI probation, this pre-arrest PAS test is optional, and you can decline it without an automatic license penalty. Officers do not always make that clear.
After a lawful DUI arrest, the rules change. Under California's implied consent law, driving on state roads means you have agreed to submit to a chemical test of your breath or blood once you are arrested. Refusing that post-arrest test can trigger a one-year license suspension on top of the DUI, and it can be used against you in court as evidence of guilt.
There are exceptions. Drivers under 21 and those already on DUI probation are generally required to submit to the PAS test, because they are subject to zero-tolerance and probation conditions.
Knowing which test you are being asked to take, and when, can change your options. Learn more about refusing a breath test and how implied consent works.
This is general information, not legal advice, and every case is different. Call Crudo Law at (858) 622-7280 or visit /contact for a free, confidential consultation.