What is a Portable Breath Test (PBT) and what is it used for in Missouri?

 Written by: Christopher Yotz

            The Portable Breath Test (PBT) machine is a hand held breath alcohol testing machine carried by police officers. There are many different brands and models used and available. Some models simply give a positive or negative result for alcohol and some attempt to give a BAC % reading. By definition, the PBT is portable and therefore not attached to anything like a vehicle or building nor used solely within either. This portability does not lend accuracy or reliability to the machine for multiple reasons. There is at least one PBT machine that is approved in Missouri for use as an evidentiary breath testing machine but it must be mounted in a specially modified vehicle or building and attached to a printer such that it allegedly lends the machine more reliability.

            The PBT is used in Missouri to attempt to show the presence of alcohol in the test subject’s blood. The test is administered prior to arrest. This alleged presence of alcohol is used to show probable cause for arrest on the charge of DWI. Even if the machine claims to give a BAC % reading, such a reading is not admissible in court to show anything other than the presence or absence of alcohol.

            Additionally, any submission to a PBT test prior to arrest is not counted toward the two evidentiary breath tests the police can demand under the Implied Consent Law. (The number of evidentiary tests allowed will be discussed in another article). The police can ask you to submit to a PBT multiple times prior to arrest. You are not required to submit to any PBT prior to arrest in Missouri. If you refuse to submit to a PBT, this refusal alone is not the one that will suspend your driver’s license for a year. Only a refusal of a legally demanded evidentiary breath, blood or urine test(s) after arrest can suspend your driving privilege.