Field sobriety tests and how they gauge a driver’s impairment

On Behalf of | Jan 21, 2023 | DWI |

It is intimidating to see the flashing lights of a law enforcement vehicle in your rearview mirror as you are driving. Even if you do not think that you have violated any traffic laws, if police suspect that your behavior indicates possible impairment, they have a valid reason to pull you over. After stopping a driver for this reason, the police will speak to the driver and may then ask the driver to submit to certain physical tasks in order to determine if further action is necessary. 

Field sobriety tests are employed by law enforcement across the country as standard ways to determine if a driver is exhibiting signs of impairment and if a chemical test is necessary. These three tests have a person do seemingly simple tasks, during which the law enforcement officer will be observing the driver’s eyes, physical reactions and coordination closely. Law enforcement receives training on how to properly administer these tests. 

What types of tests could you expect? 

There are three standard field sobriety tests that law enforcement may administer during a suspected drunk driving traffic stop. The intent of these simple tests is to allow an officer to evaluate a driver’s ability to follow directions, coordination and physical reactions, all things that may be reduced after consuming drugs or alcohol. The three standard field sobriety tests include: 

  • Walk-and-turn test – During this test, the officer will ask the driver to take nine steps, stop, turn and return to the starting point. The driver must walk heel-to-toe in a straight line. This test evaluates a driver’s balance and ability to follow instructions. 
  • Horizontal gaze nystagmus – During this test, the officer will have the driver follow a moving object, such as a pen, with his or her eyes. If there is an involuntary jerking of the eyeballs, it could indicate impairment. 
  • One-leg stand test – During this test, the driver will balance on one foot and count until the officer says to stop. The officer will be looking for hopping, swaying, difficulty balancing and having to use the arms to stay in position. 

These tests are standard, and Minnesota officers must administer them in specific ways. If you believe there was a problem with the administration of field sobriety tests during your traffic stop, or you are facing DWI charges after the failure of these tests, you will benefit from seeking an understanding of your defense options. You have the right to fight any criminal charges and confront the case brought by the prosecution.  



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