A field sobriety test is a test the police use to determine if you are driving under the influence. Driving under the influence impairs your driving ability; hence, these tasks assess your coordination, balance, and ability to divide your attention to more than one task.
If you fail the field sobriety test, then the officer will then ask you to take a breath test or chemical test to confirm your blood alcohol content.
Note that according to the National Highway Traffic Safety Administration, there are three types of field sobriety tests, as described in this article.
Alt: Police Traffic Stop
Walk and Turn Test
The test is sometimes referred to as the nine-step test or DUI straight line test because it requires you to walk nine heal-to-toe steps along a straight line. After taking the nine steps, you are then instructed to turn around on one foot and return in the same exact manner in the opposite direction.
Officers look for indicators of impairment, such as if you cannot maintain balance, lose your balance while turning, take an incorrect number of steps, and stop walking mid-steps, amongst other things.
If a driver exhibits two or more clues, it means there’s a 68% chance the driver has a block alcohol level of 0.10%. However, despite the NHTSA report on the accuracy of this test, drivers with medical conditions, disabilities, age, and injury may fail this test.
In such a case, having an Indianapolis DUI lawyer defend you will go a long way so you don’t get your license suspended, a heavy fine, or even worse.
Horizontal Gaze Nystagmus
Nystagmus is a medical condition that refers to the involuntary or bouncing jerks of the eyes; hence the name horizontal gaze nystagmus test, which checks for pronounced involuntary movement of the eyes.
An individual who is impaired by alcohol or drugs, primarily depressants, experiences significantly exaggerated involuntary jerking of the eyeballs.
Officers conduct the horizontal gaze nystagmus test in a well-lit area or with a flashlight. The officer then asks if you have any eye condition or wearing contact that could affect the results. The officer then asks you to stand a few feet away, and with a small object 12 or 15 inches from your face slightly above eye level, the officer then moves the object side to side and asks you to follow it with your eyes. The officer will follow your movement to determine the following:
- If the angle of the jerking onset is within 45 degrees
- If jerking is distinct when the yes is at maximum deviation
- If the eyes cannot follow the object smoothly
- Equal pupil size and equal tracking in your eyes
- If pupils move at different rates
If, based on this test, you fail four or more clues, it means there’s a 77% chance you have a blood alcohol concentration level of 0.10% or greater.
One-leg Stand Test
The one-leg stand test is a sobriety test to assess if your focus and stability are impaired. In the test, the officer will ask you to stand on one foot at about six feet off the ground and count from 1001.
During the test, the officer looks for indicators of impairment, such as putting your foot down, hopping to maintain balance, swaying while balancing, and using your arms to balance yourself.
This test has an accuracy of 65% in predicting if a driver has a blood alcohol level of 0.10%.
