An officer sometimes requests a Preliminary Breath Test, or PBT, during the course of a DWI investigation. If the officer makes such a request of the operator of a vehicle, it is normally roadside, after the driver has done the standardized field sobriety tests but before any arrest. Unlike the request for a breath test after an arrest, there is no written form for the driver to sign. The officer will make the request verbally. The officer must inform the driver that, whether or not they agree to a PBT, it does not prevent a subsequent, post arrest breath or blood test. If the driver agrees to the test, the results must be provided immediately. However, the results can be provided verbally unless the driver requests that the results be furnished in writing.
If the driver refuses to take a PBT, such a refusal is not admissible in court (except for the limited purpose of establishing probable cause for the arrest if the driver asserts that there were insufficient facts to be support the arrest). However, if the driver agrees to take a PBT, the results of such a test are admissible for “any purpose” in court, but most judges give it little weight in deciding your quilt beyond a reasonable doubt as the PBT devices do not have most of the safeguards that the Intoxilyzer has.
But why risk it? If you are requested by the police to take a PBT test, it probably means that the officer is concerned about whether he or she has enough evidence to arrest you without it. In other words, whether he has sufficient probable cause for the arrest. Do not take the test unless you have consumed NO alcohol.