If you ae like most people in Minnesota, you know that part of a drunk driving investigation includes an officer asking a driver to perform certain tests at the location at which they have been stopped. If you assume that these tests are completely accurate, you would be incorrect. As explained by FieldSobrietyTests.org, each of the three tests administered has a known inaccuracy rate.
One test is called the horizontal gaze nystagmus test. It is the most accurate of the three tests and yet is still has an accuracy rate of only 77%. Your physical health may well contribute to your inability to pass this test as certain neurological or ophthalmological conditions might interfere with the results. A nystagmus is a normal jerking of the eyeball that can be exacerbated due to health conditions or possibly due to the consumption of alcohol.
Signs an officer looks for in determining if you pass this test or not include if your eyes can track a light or object together and if your eyeball jerks before it reaches a certain angle when tracking. The officer will also look to see if both of your pupils are the same size. How smoothly your eyes track may also play into the officer's assessment.
If you would like to learn more about the horizontal gaze nystagmus test or other test results and evidence that may be used against you after a DUI arrest, please feel free to visit the drunk driving defendant's rights page of our Minnesota criminal defense website.