When a police officer wants to determine if a driver is impaired, they may give them field sobriety tests. Failing these tests is often enough for arrest. The three main tests that are used are known as the horizontal gaze nystagmus (HGN) test, the walk-and-turn test and the one-leg stand test.
Unfortunately, reports have found that these aren’t exactly reliable. The one-leg stand test only provides correct results in 65% of cases, for example, and the walk-and-turn test isn’t much better at 68%. Even the HGN test, known as the most reliable of the three, clocks in at just 77%. If the police administer these tests to just 10 different drivers, there’s a good chance that they will get numerous false positives.
You can fail the test without being impaired
Perhaps the biggest reason for this lack of reliability is just that a person can fail any of these tests, even if they haven’t been drinking.
For example, someone may fail the walk-and-turn test because they’re nervous, so they weren’t paying close attention to the directions. They could fail the one-leg stand test if they’re feeling fatigued after a long day of work. Environmental issues may also play a role. It may be more likely that someone would fail the test if it’s dark outside and there’s reduced visibility while they’re taking the test on the side of the road, for example.
On top of that, it’s possible for officers to make mistakes. Field sobriety tests are effectively just a judgment call. The police officer has to decide if they believe the suspect has failed the test. An officer’s error could lead to a false arrest.
If you have been arrested on impaired driving charges, perhaps after failing one of these unreliable tests, you need to know about all of your legal defense options.