What are SFSTs and PBT?
When a person is stopped by law enforcement and the officer thinks that the driver may be under the influence of drugs or alcohol, the officer will ask the driver to perform SFSTs. The Standardized Field Sobriety Test (SFST) is a battery of three tests administered and evaluated in a standardized manner to obtain validated indicators of impairment and establish probable cause for arrest. These tests were developed as a result of research sponsored the National Highway Traffic Safety Administration (NHTSA) and conducted by the Southern California Research Institute. US Department of Transportation. http://www.nhtsa.gov/people/injury/alcohol/sfst/appendix_a.html.
The three tests are HORIZONTAL GAZE NYSTAGMUS (HGN), WALK & TURN, and ONE LEG STAND. These are typically followed by the PORTABLE BREATH TEST (PBT).
HGN is a test to see how the eyes track while watching an object as it moves across the line of vision, for example the officer’s pen. According to NHTSA, scientific evidence says that an impaired person’s eyes will jerk back and forth as they move from left to right or right to left.
THE WALK & TURN test measures the driver’s ability to follow instructions, walk to a certain point on the ground while touching each foot heel to toe and then turning around and returning in the same manner to the starting point. Impaired drivers may have balance issues, be unable to keep count out loud and not make physical contact with the heel to the toe of the other foot.
THE ONE-LEG STAND tests the same thing as the walk and turn, however, it is performed from a stationary position.
After the SFSTs the next test is the portable breath test, also referred to as the preliminary breath test.
PORTABLE BREATH TEST is a handheld device that the officer uses to test a driver’s alcohol level while onsite. The officer will hold the PBT device and have the driver blow into a “straw” or “tube”.
Although these tests have been developed through research, there still remain questions as to their accuracy. For these tests to be accurate or valid, they must be instructed and performed in a particular manner. Many factors can influence the results, such as the officer’s preconceived notion that the driver is under the influence or the nervousness of the person attempting the tests, as well as age and physical issues.
Do I have to perform the FSTs or blow into the PBT device? Continue reading