Portable Breath Test

Each year, thousands of drivers across the nation are arrested and charged with driving under the influence of alcohol or drugs (DUI) after failing a portable breath test. But exactly how do these tests work and are their results reliable? Here are some of the most important things you need to know about portable breath tests (PBTs). 

To establish probable cause for a DUI charge, the police officer must have a justifiable reason for pulling you over (such as speeding or running a red light). Secondly, he or she must have cause to suspect you are intoxicated (such as seeing an open container of alcohol in your vehicle or smelling alcohol on your breath).And finally, the officer must have evidence, other than his or her own personal observations, to prove your BAC is above the legal limit—that’s where breath tests come in.

As you can probably guess, a breath test detects alcohol use by analyzing a person’s breath. Because alcohol remains in the system until it is filtered out by the body’s natural processes, the air you exhale also contains traces of the substance. Breath tests, therefore, work by measuring the amount of alcohol in your breath and then using that number to calculate the amount left in your system—known as blood alcohol content, or BAC.

There are two types of breath tests: evidentiary and portable breath tests. Whereas evidentiary breath tests are administered at a police station or hospital, portable breath tests are performed directly at the scene of your arrest. While breath testing laws vary from state to state, most courts do not admit PBT results due to their unreliability. As a result, they are most often used to establish probable cause for a person’s arrest.

From a legal perspective, anyone who has a BAC above 0.08% is considered impaired. As a result, if your breath test results indicate a BAC above this limit, you can expect to be arrested for DUI. Depending on the laws in your state, however, a formal evidentiary breath test may be required before you can officially be charged with the offense.

Unfortunately, most drivers are unfamiliar with the breath testing laws in their area. That’s why it’s so important to obtain legal counsel if you were recently charged with driving under the influence. In many cases, your portable breath test results may be inadmissible—and even if your state does allow these results to be used in court, there are numerous ways to challenge them.

To determine your best defense strategy, make sure you discuss your case with an experienced DUI defense attorney. Whether proving evidence inadmissible or challenging the grounds for your arrest, having legal representation can often be the difference between a conviction and an acquittal.