ABA Family Legal Guide

Automobiles

Your Automobile and the Police

Drunk Driving

How does the prosecution prove that a person was drunk driving?

The prosecution relies heavily, sometimes solely, on the arresting officer's testimony about the defendant's operation of the vehicle and the defendant's behavior (observations of the defendant's appearance, speech, and an odor of alcohol). The prosecution also relies on the results of field sobriety tests and chemical tests (breath, blood, or urine). For example, the arresting officer might give evidence that "the car was weaving over the center line of the highway," or that "the driver had slurred speech, heavy odor of alcohol, glassy bloodshot eyes, and could not walk straight."