In most DUI defense, the focus is on the blood alcoho level. However, many cases can be successfully defended because the prosecutor cannot prove you were driving. The first hurdle is to file a motion to dismiss the case, referred to by its fancy latin name – Corpus Delicti.
Here is the California Drunk Driving Law regarding proof of driving:
A “slight movement” of the vehicle in the arresting officer’s presence constitutes direct evidence that the vehicle was being driven. People v Wilson (1985) 176 CA3d Supp 1, 8, 222 CR 540. Moving the vehicle even a few inches constitutes driving. Music v Department of Motor Vehicles (1990) 221 CA3d 841, 850, 270 CR 692. If the arresting officer does not see the defendant driving the vehicle, proof that the defendant was driving may be established by circumstantial evidence (Mercer v Department of Motor Vehicles (1991) 53 C3d 753, 762, 280 CR 745), for example:
Elimination of other possible drivers. Once other possible drivers have been eliminated from consideration, the client’s proximity to the vehicle is evidence from which a reasonable inference can be drawn that the client was the driver. For example, the client who was found standing alone next to the vehicle after the accident and whose injuries were consistent with having sat in the driver’s seat was properly found to be the driver. See People v Gapelu (1989) 216 CA3d 1006, 1009, 265 CR 94. But in another case, People v Moreno (1987) 188 CA3d 1179, 1186, 1190, 233 CR 863 (corpus delicti was not established when there was no evidence that defendant was driver and there were other people at scene who may have driven); People v Nelson (1983) 140 CA3d Supp 1, 3, 189 CR 845 (corpus delicti was not established because it was possible other individuals may have been driving).
The corpus delicti for a DUI offense was also established in a case in which the officers found the vehicle parked on the side of the highway with a flat tire, the client was sitting in the passenger seat of the vehicle while her companion was changing the tire, they were the only individuals in the vicinity of the vehicle, and both were under the influence of alcohol. The court ruled the prosecution was not required to establish who was driving as a condition precedent for the admissibility of the defendant’s statement that she was the driver. Once the prosecution established that a reasonable inference to be drawn from the evidence was that a person under the influence of alcohol drove the vehicle on the highway, it was entitled to use the defendant’s statement to establish that she was the driver. It was not required to eliminate all other inferences to establish the elements of the crime of DUI. People v McNorton (2001) 91 CA4th Supp 1, 5-6, 110 CR2d 930. See also People v Martinez (2007) 156 CA4th 851, 855-856, 67 CR3d 670 (corpus delicti established by evidence that an automobile was parked facing the wrong way with its engine running and its headlights on, and evidence that there were only two people in the vicinity, one of whom was in the passenger seat with her seatbelt buckled, and one of whom was intoxicated).