A field sobriety test is something an officer may ask a driver to do if they suspect that they are impaired. The one-leg stand is a common example, as is the walk-and-turn test. Another is the horizontal gaze nystagmus test, which measures movement in the eye.
The reason for these tests is to demonstrate impairment, even without a breath test to get a blood alcohol concentration (BAC) reading. If the driver fails the test, they could be arrested because the officer will allege that they were too drunk—or under the influence of other substances—to drive legally. But are these tests actually reliable enough to be used in this manner?
They are often wrong
The unfortunate reality is that these tests are often wrong. The horizontal gaze nystagmus test is the most reliable — about 77%. The one-leg stand test is the least reliable at just 65%, while the walk-and-turn test sits in the middle at 68%.
Part of the issue is that people can fail these tests even when they’re sober. Maybe someone has an injury or a disability that makes it hard for them to balance on one foot. Maybe they’re just naturally uncoordinated or have poor balance. The officer may think they’re impaired when they’re not.
Another problem is that the officer is making a judgment call. These tests can’t be unequivocally passed or failed. The officer simply observes the person’s behavior and decides if they’re impaired. But as with anything that is a judgment call, this leaves the door open for significant human error.
Fighting the charges
Have you been arrested for impaired driving based on your performance in field sobriety tests? It’s important for you to understand all of your defense options, especially if you want to fight the charges.
