First Offense DUI

While it seems obvious, remember that the prosecution has to prove that the defendant was driving a vehicle, AND that, while driving, the defendant was “under the influence” of drugs or had a BAC above a certain limit. When the prosecution cannot show that the defendant was ever driving, or that the defendant was driving with too much alcohol in their system, then their case might be weaker.

In some DUI cases, the defendant is arrested on suspicion for DUI during a traffic stop, and testing done soon afterwards shows that they were intoxicated. In those cases, the prosecution might have an easier time proving that the defendant was, in fact, driving the car while intoxicated.

Consider the following example: Tatiana drives her car into town sober, she parks her car, walks to a bar, drinks all night, and returns to her car. She never starts her car or moves it but instead just sits inside the car and sleeps. If she was arrested and charged with DUI, she would probably be found “not guilty” because, while he did drive his car at some point, he did not do so while drink or with a high BAC.

In some DUI cases there are no test results available and the prosecution’s case rests largely on circumstantial proof that the defendant was intoxicated or under the influence of drugs or alcohol. To do this, the prosecution might base most of their case on evidence from “field sobriety tests”, if any were done. Examples of this include the “one leg stand” and “walk and turn” that police officers have DUI suspects perform before arresting them for DUI. However, field sobriety test are not always reliable indicators of intoxication. A well-prepared defense of a DUI case should look into whether police exaggerate or overstate the defendant’s “failures” on field sobriety tests, and whether other factors like the weather, the terrain, or the defendant’s physical abilities made it seem that they might be “failing” certain tests when in fact they were perfectly sober.

In many DUI cases there is chemical testing available in the form of breath or blood samples. In those cases, if the test results show that the defendant’s BAC was above the allowable amount, and the jury accepts those test results as true, then it does not matter that the defense proves that the defendant was not actually “too drunk to drive”, because driving with a BAC that is too high is still considered “DUI”.

One point that is worth clarifying: there is a difference between the “roadside” preliminary alcohol screening test and the chemical tests done after the defendant was arrested. The preliminary test (or “PAS” for short) is primarily meant to determine whether an officer has “probable cause” to arrest someone for DUI. A well-prepared defense of a DUI case should thoroughly investigate the differences between the PAS testing and any subsequent methods, because any problems might disrupt the prosecution’s ability to prove intoxication. The PAS test is always based on a breath sample. A “chemical test”, however, is usually taken after the defendant has already been arrested on suspicion of DUI. The results of this test are usually what a DUI prosecution is likely to base their case on.

While not necessarily a “defense” to a charge of DUI, a good DUI defense attorney should always explore the possibility of a “motion to suppress” any evidence taken in their client’s case. Where police obtain evidence against a defendant through unlawful means, the court might be inclined to “suppress” or “keep out” that evidence at trial, forbidding the prosecution from using it against the defendant. This is true in all criminal cases. In DUI cases, however, a successful motion to suppress might be fatal to the prosecution’s case.