A field sobriety test is used to determine whether a driver is intoxicated. Three kinds of tests are standardized for use in the field and endorsed by the National Highway Traffic and Safety Administration.
What is the walk and turn test?
With the walk and turn test, the objective is to have you walk nine steps forward from heel to toe. You must walk in a straight line and turn on one foot before returning to the starting point. Most people can do this without a problem when sober, but when intoxicated, people struggle. The trouble with this test is that those with disabilities or balance issues may also struggle, resulting in a false positive result.
What is the horizontal gaze nystagmus test?
This test looks at the way your eyes jerk to the side when you look to the left or right. Normally, they jerk a small amount, but when you’re intoxicated, that motion is more pronounced. An officer might ask you to follow a moving object smoothly as well to test your ability to focus. An issue with this test is that some people — particularly those with migraines, epilepsy and other neurological issues that may affect the eyes — could fail during a medical emergency or when symptoms are present.
What is the one-leg stand test?
Like its name suggests, the one-leg stand test is when a person is asked to stand on one leg with the other foot off the ground for around 30 seconds. Swaying or having to rebalance can be signs of intoxication, but they could also be a result of poor balance, medical emergencies or other conditions.
While these tests are accurate more than 91 percent of the time, according to statistics, they are not foolproof. You have the right to defend yourself if you’re falsely charged.
Source: FindLaw, “Field Sobriety Tests,” accessed Nov. 24, 2016