In any prosecution under this subdivision, it is a rebuttable presumption that the person had 0.08 percent or more, by weight, of alcohol in his or her blood at the time of driving the vehicle if the person had 0.08 percent or more, by weight, of alcohol in his or her blood at the time of the performance of a chemical test within three hours after the driving.

The standard elements of Vehicle Code 23152(b) are:

1. The defendant drove a vehicle;
2. When the defendant's blood alcohol level was 0.08% or more by weight.

Importance must be paid to the concurrence of the elements. The prosecution must prove each and every element, by proof beyond a reasonable doubt, that the defendant drove a vehicle with a Blood Alcohol Level of 0.08% or more.

This statute is known as the per se law. In essence, the legislature has made it a crime to drive with a BAC of .08% or more. Whether the individual was actually impaired by alcohol is irrelevant. It is enough that his blood alcohol level reached the number that the government considers evidence of impairment. Of course, that number has changed through the years, and the human body has not, so the significance of whether that number is an accurate reflection of impairment is questionable. But, it is the law, and as such, arguments that defendant was not impaired at .08% are not relevant to this charge. The following defenses are:

1. Proof of driving—driving, for DUI purposes, requires volitional movement of a vehicle. Therefore, the prosecution must prove that the defendant actually drove the vehicle. Many times, this is an easy fact to prove. But in many other cases, this is not.
   1. Many individuals are arrested at home, after a witness reported a drunk driver and the license plate. It is common for the police to run the registration information and head to the registered owner's residence. Many people have been shocked when officers arrive and arrest the registered owner for a DUI.
   2. Another common scenario is when a vehicle is on the side of the road/highway and the police approach, shortly thereafter arresting the individual of a DUI.
   3. Circumstantial evidence of driving is allowable in court. People v. Wilson (1985) 176 Cal.App.3d Supp.1, 9
   4. These cases are extremely fact specific, and the strength of the prosecution's case centers entirely around certain facts.
      1. If the prosecution can make enough of a case to prove driving, it can be extremely difficult for the prosecution to prove that when the alleged driving took place, the defendants Blood Alcohol Level was .08% or more.
   5. These scenarios can also lead to the obvious defense that any drinking that took place, or any drinking that led to .08% or more, occurred after the driving.
2. Rising Blood Alcohol – It can take up to an hour for alcohol to absorb into the bloodstream, therefore causing impairment. If the time of the last drink was close to the DUI stop, then this is a sound defense, based purely on science.
3. Title 17 violations – see section on Title 17. In essence, the evidence was not obtained properly; therefore it is not reliable evidence.
4. The police stop/arrest was improper. See section on Motions to Suppress Evidence. In essence, the police either had no reason to pull you over in the first place, or they did not have enough Probable Cause to make an arrest, or both.