When members of law enforcement suspect you are drunk, they may ask you to perform field sobriety tests.
Officers use a set of standardized field sobriety tests to gauge your level of intoxication. According to Alcohol.org, many drivers divide their attention span on the road, and field sobriety tests mimic this divided attention. There are three parts to these tests.
To complete this test, you have to stand on one leg for about 30 seconds. Law enforcement officers watch to see if you put your raised foot on the ground or extend your arms to balance. They also consider whether you hop or sway to stay balanced.
Walk and turn
You usually have to walk nine steps forward and touch your heel to your toes as you walk. Officers consider whether you can walk in a straight line without extending your arms to balance. They also watch to see if your heel touches your toes and if you take the correct number of steps.
Horizontal gaze nystagmus
Members of law enforcement usually hold up a pen or a finger and move it side-to-side. You have to follow the movement with only your eyes. The eyeball usually jerks a bit as it follows this sideways motion, a phenomenon called nystagmus. If you are drunk, you may not be able to track the sideways motion smoothly. Your eyes may also jerk more frequently.
Sometimes officers may ask you to perform additional tasks, such as saying the alphabet backward. If you do not pass these tests, members of law enforcement may charge you with driving while intoxicated. However, you may fail field sobriety tests for many reasons. You may want to seek help if you failed these tests but were not intoxicated.