DUI Wetlab & PBT testing

If you have been following our blog, you know that we conducted a wetlab, testing seven subjects to determine whether they would have been safe to drive following a typical happy hour. In our last post, we discussed roadside maneuvers. Next, we want to discuss portable breath tests (PBT’s).

Every thirty minutes we had each participant take a PBT. During a DUI investigation, an officer may ask a driver to take a PBT. The PBT is voluntary. It is important to note that a PBT is not the same as a breath test required by Colorado’s express consent law. If an officer has probable cause to believe a person is under the influence of alcohol, the officer will give an advisement that informs the driver that he has a choice between a blood or breath test. This breath test is done at the police station, not on scene, and is done on a large machine, not on a handheld device. Even if a driver agreed to a PBT, but then refuses to do either a blood test or a formal breath test at the police station, then the driver has refused testing under Colorado law.

The PBT does not count as a breath test because the results are not always reliable. PBT results cannot be used in trial. The only time a PBT result may be used is to help an officer determine whether the driver is under the influence, which helps him decide whether to arrest the driver. As you will see when we give the results of the wetlab, PBT results are not very reliable. While we did not calibrate the PBT used, the results do show that PBT’s are susceptible to errors due to things such as mouth alcohol, which is different from actual breath alcohol content.