What is a preliminary breath test?
A preliminary breath test is the breath test that the police officer will offer at the side of the road right before he places you under arrest. The results of the test are not admissible in a DUI trial, but may be admissible in the trial of other kinds of offenses--like public intoxication. Usually, a police officer will have you perform field sobriety tests like the HGN, 9 Step Walk and Turn, and One Leg Stand, and then ask you to submit to a preliminary breath test. Most law enforcement officers refer to a preliminary breath test has a PBT. One thing that's important to remember about the PBT is that an officer does not have to show you the result of the test. An officer can simply have you blow into the device and then it is his word against yours about the result of the test.
Why do most people submit to the preliminary breath test?
Most people submit to the preliminary breath test because the officer says something like, "Let's see whether you're safe to drive home." Actually, when the officer is asking you to submit to a PBT, he is gathering evidence to be used against you to convict you of DUI. Even if you blow below 0.08, an officer can still arrest you for DUI. Many people submit to the preliminary breath test because they do not realize that they can refuse to take the test. Most people also do not realize that the officer is not required to show them the results of the PBT and often will not.