Back in the 1970s, the U.S. National Highway Traffic Safety Administration realized that not all field sobriety tests were equal. In fact, many did not come close to determining whether an individual was impaired.
For this reason, the NHTSA went to work to devise a system of tests that could help law enforcement officials determine whether a driver was too impaired to safely drive.
Here’s what the NHTSA decided
By the 1980s, the agency determined that three distinct tests could provide officers with the probable cause needed to make an arrest for DUI. Since that time, the standard field sobriety tests have included the following:
- The walk-and-turn test requires you to walk heel-to-toe in a straight line for a certain number of steps before turning around and doing the same in reverse. The officer observes your ability to follow directions and maintain your balance without using your arms or starting and stopping.
- The one-leg stand test requires you to stand on one foot for a certain amount of time. The officer again observes your ability to follow directions and maintain your balance without dropping your foot or using your arms.
- The horizontal gaze nystagmus test requires you to follow an object only with your eyes. The point at which your eyes begin to jerk may reveal impairment.
The NHTSA says that the margin of error is acceptable and that, if a driver fails all of these tests, he or she is probably impaired, but that margin could be high. In addition, another problem with these tests is that they require the officer’s subjective opinion regarding whether you passed or failed the tests. You already face a certain amount of bias since the officer suspects you of intoxication or you wouldn’t have to participate in these tests.
Challenging the results of the tests
Another major flaw in the tests is that any number of physical illnesses and injuries could cause you to fail the tests, and the officer may arrest you. As you can see, if you participate in these tests and fail them, you probably shouldn’t simply accept the results since so many things could cause erroneous results.
You should also know that, no matter how much an officer presses you to do so, you are not legally obligated to participate in field sobriety tests, and considering all that could go wrong, it may be in your best interests to politely decline.