WHAT'S THE DIFFERENCE BETWEEN THE (a) and the (b) count?
Normally when someone is arrested they will see that they are charged with vehicle codes sections 23152(a) and 23152(b). Many time the cops will write the numbers .08 next to the (b) count to indicate the "per se" element of the code.
In a nutshell, the 23152(a) means that it is illegal to drive while under the influence of alcohol. 23152(b) means that it is illegal to drive with a blood or breath .08 or greater. It is interesting to note that this (b) section of the code was not added until 1982. Prior to that, the prosecution had to prove you were under the influence.
So all that this means is that the prosecution has in essence 2 opportunity to prove you were DUI.