Preliminary Breathalyzer Test

There is always some confusion in DUI and DWI cases about breathalyzer tests. In Virginia, just by driving you are deemed to have given your implied consent to take a breath test, but that breath test is the machine back at the police station.

Preliminary breathalyzer test at the scene

The police carry with them what they call a preliminary breath test (PBT). It’s a little portable breath testing machine that they use on the scene to help determine if there is probable cause to make an arrest.

You do not have to consent to a preliminary breath test. The preliminary breath test is not known to be as accurate as the machine used back at the police station. And the preliminary breath test is not admissible as evidence of your intoxication at trial.

Preliminary breathalyzer test for probable cause

But the preliminary breath test can be used to prove whether or not the police officer had probable cause to arrest you. In some DUI cases, probable cause to make the arrest can be a critical factor. If you did the preliminary breath test and it turns out that you had a higher blood alcohol content than the legal limit, then probable cause is rather solid against you.

Keep this in mind if you’re ever stopped by a police officer who offers a preliminary breath test. You do not have to consent. Then the officer would have to base his determination of whether or not to arrest you on other factors, such as your demeanor, any alcohol he might smell or see, how you were driving, field sobriety tests, and other factors.