PBT's are administered by officers out in the field, to help verify if the motorist has been driving under the influence. Because PBT's are not as accurate as the in-station DataMaster machines, the results are typically not admissible, although there are exceptions to that rule (e.g., to help defend against a challenge to the arrest; by the motorist to rebut testimony obtained by the prosecution on cross examination that the motorist’s breath alcohol was higher at the time of the offense, than when the test was administered, or by the prosecution to rebut testimony obtained by the Defendant on cross examination that the motorist’s breath alcohol was lower at the time of the offense, than when the test was administered (the “rising blood alcohol defense”)
Minors who refuse a PBT upon an officer’s request will incur 2 points on their license, while a driver over 21 will not. MCLA §257.320a(1)(u). However, an adult will incur a no-point civil infraction for refusing a request for a PBT. MCLA §257.625a(5).