People who are pulled over due to an officer’s suspicion that they might be drunk driving may be asked to take a field sobriety test so officers can determine if they are impaired. While there are many different types of these tests, only the standardized field sobriety test (SFST) is considered reliable.
The SFST is backed by the National Highway Traffic Safety Administration (NHTSA). The purpose of SFSTs is to provide a systematic method for officers to identify impairment and make more informed decisions about whether further testing or arrest is warranted.
Horizontal gaze nystagmus test
The horizontal gaze nystagmus test requires the driver to follow an object side-to-side. The officer looks for involuntary jerking in the eye that increases when a person is impaired. This test is considered by many to be the most reliable of the SFSTs, as it is less influenced by a person’s physical ability or balance. However, it’s not without its critics, who argue that various factors other than impairment can influence the results.
Walk-and-turn test
The walk-and-turn test assesses a suspect’s ability to complete tasks requiring divided attention, simulating the multitasking required for driving. In this test, the driver has to take nine steps, heel to toe. At the end of the nine steps, they have to pivot on one foot, turn and return to the starting point in the same manner. This test is designed to measure both physical and cognitive impairment.
One-leg stand test
Like the walk-and-turn test, the one-leg stand evaluates an individual’s physical control and mental focus, critical components for safe driving. The driver has to hold one foot six inches off the ground. They must count while doing this and can only stop when the officer instructs them to do so.
A person who’s facing drunk driving charges may call an SFST into question as part of their defense strategy. Working with a legal representative who’s able to evaluate the situation, explain the options to the defendant and help them to craft a defense that shows their side of the matter in the most effective manner possible is generally advisable, given how much is at stake in cases like this.
