If an Alaska law enforcement officer pulls you to the side of the road for any reason, and he or she has a reason to believe that you may have been drinking, you may have to take a standardized field sobriety test. This battery of three tests can indicate a blood alcohol content of 0.08 percent.
AAA points out that even though courts often consider test results to be scientific evidence, they may be flawed.
Involuntary eye movement
When the officer asks you to track the movement of a pen or a finger, this is not to determine whether your eyes will focus. Instead, he or she wants to see if your eyeballs jerk at a certain angle. This is horizontal gaze nystagmus. You probably will not feel it if you have nystagmus. In fact, you could already have it and not know because a number of health issues and medications may also cause this condition.
A study verified that this test can identify subjects with 0.08 percent BAC about 88 percent of the time.
Alcohol makes it difficult for the brain to multitask. When an officer tells you to walk in a straight line, heel-to-toe, for nine steps, then turn around on one foot and walk back the same way, you may have trouble keeping the instructions in mind while you attempt to carry them out if you have a BAC above the legal limit. You may also have trouble keeping your balance.
This test is the least reliable of the three, according to that same study. More than 20 percent of the people who exhibited two or more signs of impairment during this test had a BAC below 0.08 percent.
The one-leg stand test primarily involves balance. You must keep one foot in the air for 30 seconds without putting your arms out, hopping or swaying. Any number of physical factors may affect a person's balance, though, including inner ear issues, vertigo, medication and age.
Approximately 83 percent of the people in the study who showed two of the four balance issues did, in fact, have a BAC of 0.10 percent or higher. However, 17 percent did not.
If you are aware of an issue that would affect your ability to complete the tests successfully, you should tell the officer before you begin.