We all probably know that the legal limit for a DUI is “.08” However, I frequently speak with individuals who are below the "legal limit" but still get arrested for driving under the influence and they wonder how that is possible. The answer is that there are actually two parts to California’s DUI statute. The statue is found in the Vehicle Code at section 23152 which states:
23152. (a) It is unlawful for a person who is under the influence of any alcoholic beverage to drive a vehicle. (b) It is unlawful for a person who has 0.08 percent or more, by weight, of alcohol in his or her blood to drive a vehicle.
So drunk driving actually can happen two different ways: One way is driving with a blood alcohol at or over a .08 as contained in paragraph “b”. This is often referred to as the ‘per se’ law, meaning the law is violated automatically regardless whether the driver is impaired or not. Of course, this ‘presumption’ of impairment or accuracy of the test results can be challenged or rebutted.
The other part of the statute in paragraph “a”, requires actual proof of driver impairment for there to be a conviction of DUI. However, impairment can occur for some people well below a .08! So the difference between 23152(a) and 23152(b) is that proof of alcohol impairment (usually some sort of bad driving) is required for the “a” count where only a minimum blood alcohol level is required for the ‘b’ count (even where there is no bad driving)
Importantly, prosecutors usually will charge a violation of both parts of the statute just in case the blood or breath test results are thrown out or the accuracy is seriously called into question. They can also charge a DUI if the test results are actually below a .08 and this is how sometimes even if the driver blows below a .08 they can still find themselves being arrested and charged with driving under the influence. All the more reason to be careful, even with only a couple of drinks at dinner.