A person who’s pulled over for suspicion of drunk driving may be asked to take a roadside breath test to determine their blood alcohol concentration (BAC), which is one factor that’s used to determine if a person should be arrested. The legal limit for drivers who are 21 years old or older is .08%. Once a driver’s BAC reaches that amount, they’re considered intoxicated.
It may surprise some drivers to learn that the roadside breath tests that are routinely done aren’t admissible in court. These tests are known as preliminary alcohol screening (PAS) devices. They’re meant to give police officers a way to determine a person’s BAC, but the officer will instead need to obtain a test using a stationary breath test, a urinalysis or a blood test if they want to have results that are permittable in court.
Why aren’t PAS device results admissible in court for drunk driving cases?
PAS devices are considered too inaccurate to use in a criminal case. One of the primary issues is that it’s difficult to keep them properly calibrated, partly because they’re mobile. It would be difficult for the officer to show that the calibration was correct at the time of the traffic stop.
If the PAS device test result indicated impairment, the officer will conduct an arrest and have the person take a more reliable test that can be admissible in court. The presence of a BAC chemical test is only one component of a drunk-driving case. Anyone who’s facing drunk-driving charges should ensure they work with someone familiar with these matters so they can learn their options for building a defense strategy.