A "per se" DUI means you can be charged simply because your blood alcohol concentration was 0.08 percent or higher, whether or not you actually seemed impaired. It's the charge under Vehicle Code 23152(b), and the Latin phrase "per se" just means "by itself." The number alone is enough.
This is different from the impairment charge under 23152(a), which requires the state to show your driving was actually affected. With a per se charge, the prosecutor doesn't have to prove you were a bad driver that night. If the chemical test says 0.08 or above, the law treats that as the violation on its own. Most DUI arrests get filed as both counts, giving the DA two ways to win.
That sounds airtight, but it isn't. The whole per se charge rests on one thing: the accuracy of the BAC number. And that number can be wrong. Breath machines drift out of calibration. Blood samples get mishandled, contaminated, or stored badly. The timing of the test matters, because alcohol is still rising in some people well after they stop driving, so the driving-time BAC may have been lower.
Attack the number and you attack the per se charge at its foundation. That's a core part of DUI defense.
Our BAC defense page explains how these numbers get challenged, and our implied consent page covers the testing rules.
Questions about your test result? Call (858) 622-7280 or visit our contact page for a free consultation.
This is general information, not legal advice.