Police officers who pull over a driver because they have reason to believe the driver is drinking need to try to determine if that’s truly what’s going on. There are several ways for them to do this. One is to find out their blood alcohol concentration (BAC). This is done using a preliminary alcohol screening (PAS) device, which is a handheld device that tests a driver’s breath to provide a BAC value.
A PAS device is a non-invasive option that can provide a quick result for the officer. While it’s a useful tool for these traffic stops because it provides important information to let the officer know what to do, there are limitations that must be considered for these devices.
Recognizing the limitations
The PAS device isn’t as accurate as breath test equipment that’s more sophisticated and stationary. Those more accurate devices are typically found in police departments. The PAS device is subjected to changes in environmental conditions and constant movement of the police vehicle. These factors, as well as others, can negatively impact the calibration of the device so it doesn’t provide reliable readings.
Another limitation is that the results from a PAS device are generally not admissible in court as sole evidence of intoxication. They are intended for initial assessment and to support further testing, not to convict someone of driving under the influence. Only testing from blood tests, urine tests or the larger stationary breath testing devices are considered accurate enough to be admissible in court.
Anyone who’s facing drunk driving charges should ensure they understand their defense options, including potentially challenging BAC results. Working with someone who’s familiar with these matters may be beneficial for those defendants.