Police use standard field sobriety tests or SFSTs to determine if a driver is drunk or not. If you’re that driver and you fail such tests, you will likely face arrest for driving under the influence.
The purpose of field sobriety tests is clear. Their reliability, however, is still up in the air. Many even dismiss SFSTs as downright inaccurate.
Types of SFSTs
The National Highway Traffic and Safety Administration (NHTSA) recommends the use of three SFSTs:
1. Horizontal Gaze Nystagmus (HGN)
The HGN test is designed to detect signs of nystagmus, a vision condition that makes it difficult for a person to control eye movement. There is a link between nystagmus and alcohol intoxication, which can cause one’s eyes to jerk involuntarily.
HGN is usually done by asking drivers to follow with their eyes a small object they’re moving side to side in front of their faces. Nystagmus becomes apparent if the eyes appear to twitch a lot as they follow the object’s motion.
2. Walk And Turn (WAT)
In a walk and turn test, police will ask a driver to take nine heel-to-toe steps, turn on one foot, then go back and take the same number of steps, all in a straight line. Police expect drivers who aren’t drunk to complete the test without a hitch.
3. One-Leg Stand (OLS)
Drivers undergoing the one-leg stand test will have to be able to stand on one leg for approximately 30 seconds. To avoid a DUI arrest, they must do their best not to sway, balance themselves with their arms, hop, or put their other foot down for the test’s duration.
Why SFSTs Are Prone To Inaccuracies
Police may have been doing SFSTs for a long time, but there is still little assurance that they report accurate results all the time.
A walk and turn, for example, may turn out to be difficult to pass even for someone who’s not drunk. The ground they’re doing the test on might be uneven and cause the driver to trip. The lighting conditions might be too dark, making it hard for drivers to see whether they’re going in a straight line.
The physical condition of the driver may also come into play. For all you know, a driver actually experiences nystagmus symptoms all the time, which means he or she has difficulty controlling eye movements, regardless of whether there is alcohol involved.
On the other hand, the one-leg stand may put people with balance problems, stamina issues, or arthritis at risk of facing arrest for DUI. The same goes for people suffering from anxiety disorders, which will likely render them too uneasy to take nine heel-to-toe steps in a straight line and back.
The arresting officers also play a huge role in the outcome of any SFST they make drivers go through. After all, they’re the ones who will assess how well a driver did during the tests. That, by itself, already makes it clear that the whole thing is far from being objective. A person could end up facing DUI charges based on a police officer’s very subjective evaluation. Police officers are also not immune to committing mistakes in administering the FSTs or simply acting out of malice.
No matter how you look at it, SFSTs are not always accurate, and are, therefore, not reliable. If you were arrested on suspicion of DUI for failing a field sobriety test, you could rely on a skilled and experienced DUI attorney to challenge the results of those FSTs and improve your chances of a positive outcome in your drunk driving case.