Why is the Most Important Evidence in DUI Cases Always Destroyed?

Posted by Lawrence Taylor on September 6th, 2011

As we all know from watching TV, the police are always very careful to preserve the evidence in criminal investigations…

Except in DUI investigations.

What is the single most important piece of evidence in most drunk driving cases? The Breathalyzer test, of course  In fact, it’s the only evidence offered to prove the crime of driving with over .08% blood alcohol. And it’s pretty important to the related charge of "driving under the influence", too: the law presumes the defendant is under the influence if the test result is .08% or higher.

Evidence just doesn’t get more important than that.

So, of course, the police are careful to preserve the breath sample, right? I mean, there may be some question later of whether the machine was working correctly; it would be a simple matter to save the breath sample so it could be tested again on another machine. And, hard to believe, but the defense may not want to just take the officer’s word that the test results were from the defendant’s actual test.

Unfortunately, the breath sample is routinely destroyed moments after it is tested.

But how can this be? That’s a question that was asked a few years ago by a defendant in California appealing his DUI conviction. The Court of Appeals of that state agreed and reversed the conviction:

Due process simply demands that where evidence is collected by the state, as it is with the Intoxilyzer, or any other breath testing device, law enforcement agencies must establish and follow rigorous and sytematic procedures to preserve the captured evidence or its equivalent for the use of the defendant. People v. Trombetta, 142 CalApp.3d 138 (1983).

How hard is it to save the defendant’s breath sample for later retesting? The Court noted that a "field crimper-indium encapsulation kit" was readily available, cheap and approved by the California Department of Health Services. So why isn’t the evidence saved in DUI cases today?

The Trombetta case was eventually appealed by the state to the United States Supreme Court….where it was reversed:

"Whatever duty the Constitution imposes on the States to preserve evidence, that duty must be limited to evidence that might be expected to play a significant role in the suspect’s defense. To meet this standard of constitutional materiality, evidence must both possess an exculpatory value that was apparent before the evidence was destroyed, and also be of such a nature that the defendant would be unable to obtain comparable evidence by other reasonable means. Neither of these conditions is met on the facts of this case." California v. Trombetta, 467 U.S. 479 (1984).

What? Neither of these two conditions is met in a DUI case? Let’s take another look at the Supreme Court’s test:

1. The possible value of the defendant’s breath sample in helping prove innocence was not apparent before it was destroyed…..

What? The machine never makes mistakes? It was not apparent to the police that a re-analysis of the all-important breath sample might be of any value to the suspect?  And if not, how is any defendant supposed to prove that value?

2. The defendant was able to "obtain comparable evidence by other means"…..

How? He has no access to another breath test. At best, he might be able to get a blood test at a hospital, if the police let him — but it would probably be so much later that it would not be relevant or even admissible in court.  And the cops are unlikely to accommodate him: why would they want evdience that might contradict their own evidence?  And besides, it takes too much time and effort to go to a hospital.

Another example of  The DUI exception to the Constitution.

It’s interesting that the New Hampshire Supreme Court later rejected the Supreme Court’s reasoning, and relied upon its own state constitution in requiring breath samples to be saved:

A suspect would face numerous practical difficulties in obtaining a second sample on his or her own. While in police custody, the suspect would have to locate an available, licensed technician capable of promptly performing a second test, no matter what time of day or night. Even if a defendant successfully obtained an independent second test, the results would not have the same evidentiary force as would a second test performed on the same machine at approximately the same time.  Opinion of the Justices, 557 A.2d 1355 (1989).

The Trombetta decison was, as intended, a huge green flag to police agencies across the country: Go ahead and destroy the main evidence — but only in DUI cases. And law enforcement agencies have happily complied ever since.