Police officers use field sobriety tests to help determine whether or not a person may be intoxicated. These tests are designed to evaluate the suspect’s motor function, balance, and memory capabilities, all of which can be affected by the consumption of alcohol or abuse of illegal drugs. Three of these tests have been standardized to help ensure a fair evaluation of all suspected drunk drivers. They are as follows:

Horizontal Gaze Nystagmus (HGN)
Excessive alcohol consumption can affect the muscles that control a person’s eyes. To conduct this test, the officer will have the driver hold their head in a straightforward position while following a moving object (such as the officer’s finger) with their eyes as it moves side to side. If the suspect’s eyes twitch or spasm when looking to the far right or left – a phenomenon is known as nystagmus – then the individual could fail the HGN test.

Walk and Turn (WAT)
Commonly referred to as “walking the line,” the WAT evaluates a person’s divided attention. They will be asked to walk a certain number of steps along a straight line, such as a lane line while counting them out loud. They will then have to turn and repeat the action. Loss of balance, losing count, or forgetting instructions could all result in failure of this test.

One-Leg Stand (OLS)
The OLS is also a divided-attention test. The person will be required to stand on one leg with their arms outstretched and count out loud to a certain number. If they lose their balance, lose count, or forget instructions, they could fail the test and face a DUI arrest.


Field sobriety tests are not concrete evidence of intoxication. A person could also fail these tests due to a medical condition, an injury, weakness, illness, fatigue, stress, or even fear. The intimidation and fear of being pulled over in the first place can be enough to affect the results of a field sobriety test. If you were wrongfully charged with DUI due to any kind of sobriety test, contact Okabe & Haushalter for capable and aggressive defense.

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