Admissibility of Roadside Breath Test at Trial

The Portable Breath Test, or PBT, is commonly used by law enforcement officers to obtain a sample of someone’s breath to determine what BAC level he or she has.  These portable devices are most often used during a traffic stop on the side of the road.  This portable test is much different then the “Intoxilyzer” that is used down at the police station. That test is admissible into evidence to prove your Blood Alcohol Level, either through the breath test or through drawing blood if the breath test is to difficult to administer.

A common question that arises is whether this reading is admissible as evidence or is it merely an investigative tool?  Taking a sample of someone’s breath is considered a search and is protected by the 4^th amendment.  Thus in order for police to take a breath sample they must either obtain a warrant or fall within one of the exceptions to the warrant requirement.

In North Carolina the law agrees that a breath sample taken when the police have probable cause to believe a driver is driving intoxicated will fall within the exigent circumstances exception. 

The reasoning behind this that there is a high public interest in keeping intoxicated drivers off the road and that if the police spend time obtaining a warrant evidence of a person’s BAC will diminish.  The time taken to get a warrant may take 2-3 hours and during that time alcohol in someone’s system is vanishing thus destroying evidence.  Basically in NC as long as a police officer has reason to believe someone is driving intoxicated he may take a breath sample without violating the 4^th amendment.

Although it is the PBT breath sample is a search that does not violate the 4^th amendment when used to investigate DWI, it is generally inadmissible in a trial but may be admissible in the pre-trial.