Field Sobriety Test
The Standardized Field Sobriety Test isn't just one test, it is a series of usually three, sometimes more tests that are given by a police officer in order to evaluate whether or not someone is driving under influence. All of these tests were drafted after long research was done by the National Highway Traffic Safety Administration. All police officers must undergo SFST training in order to understand how these tests work, and how to tell if someone is drunk or under the influence of drugs. Of course you may think that just by looking or being near someone that you can tell they are drunk, but police officers need a more systematic method of evidence collection to charge a person with a DUI or another offense.
What are the most commonly used tests?
The most common field sobriety tests administered are the walk-and-turn, the one-leg stand, and the horizontal gaze nystagmus (HGN). All of these tests are used to determine if someone is impaired.
The walk-and-turn test requires the driver to take nine steps, heel-to-toe in a straight line. Once finished, the person must turn on one foot in walk another nine steps in the same manner back towards the starting position. The police officer will determine the person is impaired by looking for a lack of balance, starts to do the test before instructions are given, stops to keep balance, cannot count the number of steps taken, or isn't able to walk heel-to-toe.
The one-leg stand test is also used. This test is simple and requires the driver to stand on one foot, which the other foot off the ground, and then count by thousands aloud to the police officer. The police officer will then instruct the person to put his leg down. This goes on for 30 seconds. Here, the officer will look for swaying, hopping to keep balance, or constantly putting a foot down.
A third field sobriety test used is the horizontal gaze nystagmus (HGN) test. This test determines whether nystagmus occurs at a certain angle. Nystagmus is when the eyeball involuntarily jerks due to natural reaction. In a normal situation, this will occur when the eyes are put into high peripheral angles. If someone is drunk, nystagmus may occur at lesser angles. This test involves the subject following a small flashlight with his/her eyes. The police officer will see if the person is able to follow the object, and will note when the jerking occurs.
What other kind of field sobriety tests are used?
There are several other tests used to check for sobriety. Another very common test is the breathalyzer test in which the subject blows into a device that will record his/her BAC level. The number given by the device will determine whether or not that person is drunk or impaired.
