Exploring the Three Standard Field Sobriety Tests- A Comprehensive Guide

What are the three field sobriety tests?

When it comes to determining whether a driver is under the influence of alcohol or drugs, law enforcement officers often use a series of field sobriety tests. These tests are designed to assess a person’s physical coordination, balance, and mental acuity. The three most commonly used field sobriety tests are the Horizontal Gaze Nystagmus (HGN), Walk and Turn, and One-Leg Stand tests. Understanding these tests can help individuals better prepare for them and know what to expect during a traffic stop.

1. Horizontal Gaze Nystagmus (HGN)

The Horizontal Gaze Nystagmus test is one of the most reliable field sobriety tests for detecting alcohol impairment. During this test, the officer observes the suspect’s eye movements while they follow a moving object with their eyes. Nystagmus, or an involuntary jerking of the eye, is a common sign of alcohol intoxication. The officer looks for three specific clues during the HGN test:

– Lack of smooth pursuit: When following the moving object, the eyes should move smoothly. If they are jerky or uncoordinated, it may indicate alcohol impairment.
– Distorted or darting eye movements: The eyes should not dart around or move erratically. If they do, it could be a sign of alcohol intoxication.
– Onset of nystagmus before 45 degrees: Nystagmus should not begin until the eyes are at a 45-degree angle from the center of the head. If it starts earlier, it may indicate alcohol impairment.

2. Walk and Turn

The Walk and Turn test is designed to assess a person’s balance and coordination while walking. During this test, the officer asks the suspect to take nine heel-to-toe steps along a straight line, turn around, and then return the same number of steps. The officer looks for the following clues to determine if the suspect is impaired:

– Lack of balance while standing: The suspect should be able to stand with their feet together and arms down at their sides without swaying or using their arms for balance.
– Inability to follow instructions: The suspect should be able to follow the officer’s instructions and perform the test correctly.
– Inaccurate heel-to-toe walking: The suspect should be able to walk heel-to-toe without stepping off the line or taking an incorrect number of steps.
– Inability to turn around: The suspect should be able to turn around and return to the starting point without difficulty.

3. One-Leg Stand

The One-Leg Stand test is another field sobriety test used to assess a person’s balance and coordination. During this test, the officer asks the suspect to stand on one foot with the other foot raised about six inches off the ground. The officer then counts for 30 seconds while observing the suspect’s balance. The following clues indicate possible alcohol impairment:

– Swaying or balancing on the foot: The suspect should not sway or use their arms for balance.
– Hopping: The suspect should not hop or put their foot down to maintain balance.
– Counting inaccurately: The suspect should be able to count correctly for the entire 30 seconds.

Understanding these three field sobriety tests can help individuals prepare for them and know what to expect during a traffic stop. It’s important to remember that these tests are designed to detect alcohol impairment, and officers are trained to look for specific clues that indicate a person may be under the influence. If you are pulled over and asked to perform these tests, it’s crucial to follow the officer’s instructions and remain calm.