When an officer pulls a driver over and requests them to take a DUI test, they will often start off with a field sobriety test. This is the least invasive form of checking for someone’s potential BAC levels, and depending on results, officers can decide if they want to run further tests or not.
Since it often serves as the first line of testing for drivers, it is important to understand exactly what a field sobriety test is and how it works.
Types of field sobriety tests
Very Well Mind discusses field sobriety tests and how they fit into an officer’s DUI detection arsenal. As mentioned, this is often the first type of test used to detect potential DUI cases. Most officers use standardized field sobriety tests due to the unified rubric. Three standardized tests exist, including the horizontal gaze nystagmus, the walk-and-turn and the one-legged stand.
Each field sobriety test checks a person’s balance, coordination and ability to follow directions. The higher someone’s BAC level, the worse they generally are at completing these tests up to standard.
Problems with these test results
At the same time, field sobriety tests hold a certain level of notoriety for their inaccuracies. After all, the result of the test often depends on the officer administering it. They serve as the sole source of interpretation for a driver’s words, behaviors and actions, which means personal bias can and does come into play.
Due to this, many courts do not accept field sobriety test results alone as evidence of DUI. This is why many officers will follow it up with a breath or blood analysis test.