Driving Symptoms

The first type of evidence that will be presented to the jury by the prosecution will be the arresting officer's observations of the defendant's erratic or otherwise unusual driving symptoms—what attracted the officer's attention in the first place. In the rare case where the officer witness did not observe driving, such as where there has been an accident, then that portion of the corpus delicti will be supplied by lay witnesses or by circumstantial inference.

How important are the driving symptoms in a DUI case? Most DUI defense attorneys would probably consider the blood-alcohol evidence to be the most critical, followed perhaps by field sobriety tests. But the view of many experienced prosecutors is that the single most important area in obtaining a conviction is police testimony concerning the defendant's driving.

A manual prepared by one of the largest prosecuting agencies in California recognizes four major categories of evidence: driving symptoms; appearance and demeanor; FSTs; and blood-alcohol test or refusal. Of these, the manual states, driving is the most important—and field sobriety tests, "which are not generally viewed by jurors as highly persuasive," the least.

While the author does not necessarily agree with this view, it may be helpful to understand what the view of one's opponent may be.

Typically damning testimony would involve the officer initially observing the defendant's car traveling at a high rate of speed. For example: as the officer began pursuit, the officer noticed that the car weaved across lane lines on five occasions; at one point, the defendant failed to stop for pedestrians who were crossing in an intersection. When the officer finally decided to turn on his flashing red lights, the defendant failed to pull over for a quarter of a mile; when he did, he parked at an odd angle to the curb, the rear of his car presenting a hazard to passing traffic.

How does the DUI lawyer deal with testimony of damaging driving symptoms? Each case is different, of course, but it is rarely productive to engage in a frontal attack on the officer—to premise a defense on the sole theory that the officer is a liar and is trying to hang your client for some unknown reason. The usually more effective approach is to take each observation, one at a time, and suggest reasonable explanations for the observed conduct—and thus, a reasonable explanation for why the officer believed (mistakenly) that the client was intoxicated.

1 of 4« Previous | Next »

Back to Top