What is a “Per Se” DUI?
What does a DUI “per se” actually mean? “Per se” is a Latin term meaning “by and of itself.” Under California law, a blood alcohol level (BAC) of 0.08% is by and of itself considered driving under the influence. (For some drivers such as those with commerciallicenses, the per se BAC is lower under the law.) It doesn’t matter if the driver is not impaired at all (although this may be unlikely); if his or her BAC tests at 0.08% or above, that driver is – to use another Latin term–ipso facto under the influence.
California DUI law makes it unlawful to drive under the influence of any alcohol beverage (Vehicle Code section 23152(a)) AND to drive with a BAC of 0.08% (Vehicle Code section 23152(b).) Why the two distinctions? Well, under subdivision (a), a person could be arrested and charged even if his or her BAC is under 0.08% if the officer believes the driver is impaired by alcohol. Subdivision (b) is the “per se” part of the DUI law. When a person is arrested for DUI, they are almost always charged under subdivision (a) and (b). The need for a per se law is evident. Without it, drivers would be subject to the officer’s own subjective determination. The inconsistencies in arrests and convictions would pose a problem. Furthermore, having a per se law establishes a cut-off point where a driver is subject to arrest.