What is the primary purpose of using a preliminary breath test (PBT) during a traffic stop?

The primary purpose of using a preliminary breath test (PBT) during a traffic stop is to determine a driver's blood alcohol concentration (BAC) at the scene. This device provides officers with immediate evidence of a driver's level of alcohol impairment. By obtaining this preliminary measurement, officers can make informed decisions about whether to proceed with further investigations or sobriety tests.

Using a PBT serves as a quick and efficient means for law enforcement to assess potential intoxication, which is critical during traffic stops where impairment is suspected. If the PBT indicates a BAC that is above the legal limit, it strengthens the case for further action, such as arrest or administering standardized field sobriety tests to obtain additional evidence of impairment.

While the other options involve elements of the enforcement process, they are not the primary purpose of the PBT. For instance, issuing a citation or preparing for field sobriety tests can follow the use of a PBT but are not its main goal. Similarly, while evidence for future prosecution may be gathered based on the results of a PBT, the immediate intention is focused on determining BAC at that moment in time.