PBT devices are too inaccurate . . . to prove innocence?

A preliminary breath test (PBT) is a small handheld breath testing device used by police officers to determine whether or not to arrest a person for DUI. Typically, administration of the PBT follows field sobriety tests. Based upon a motorist’s performance of field sobriety tests and the results of the PBT, a police officer makes a determination to arrest or release the driver.

PBTs are also used to convict minors of “possessing” alcohol. When police are summoned to an underage party where they suspect minors have consumed alcohol, PBT testing results can be used to establish that a minor had consumed alcohol. Courts regularly accept these PBT results, concluding beyond a reasonable doubt that the minor had consumed alcohol based upon the test.

But what if the PBT establishes that a driver is under the legal limit?

Livingston County District Court Judge Theresa M. Brennan recently ruled that a person accused of driving drunk could not rely upon a preliminary breath test to establish his innocence. Despite the fact that this judge routinely relies upon PBTs to justify arrests and even to convict minors of consuming alcohol, Judge Brennan held that PBT results are “too unreliable” to disclose to jurors. Too unreliable? Or is it that Judge Brennan is so pro-prosecution that she feels it is undesirable to let an innocent man escape a wrongful conviction?