If you are stopped by a police officer for any reason while driving — a broken taillight or speeding – that officer is going to check for signs of impairment. That is part of the job.
If the officer suspects that you are impaired, you might be asked to step out of your vehicle and perform a few tests, which together comprise the standard Field Sobriety Test (FST). Essentially, these tests are used to judge your ability to multitask: they divide your attention between two actions. If you aren’t coordinated or clear-headed enough to perform the actions together, then it’s a fair guess that you’re not in shape to drive a car.
- Horizontal Gaze Nystagmus Test: You are asked to follow a moving object (such as a pen) with your eyes. If you’re impaired, your gaze will be jittery as opposed to smooth.
- Walk and Turn Test: As the name implies, you must walk heel-to-toe and then reverse direction. Not hard when you’re sober, but a drunk person will have difficulty balancing. If you use your arms for balance, fail to walk heel-to-toe, pause to regain balance, or – and this is important — fail to follow instructions, you won’t pass.
- One-Leg Stand Test: You raise one leg about six inches off the ground, keep it pointed straight out, and count to thirty. If you weave, put your foot down, or hop, you should prepare for some more testing.
There are other tests too, such as closing your eyes and touching your nose, reciting the alphabet, and counting backwards, but the three outlined above are considered reliable indicators of impairment.
If you fail one or more of those tests, the next step is a PBT (portable breathalyzer test). Depending on the results, you could be taken in for a blood test, which will give conclusive evidence of impairment or non-impairment.
The Field Sobriety Test on its own is not infallible, but taken together, these tests have been shown to be 80% to 90% accurate. Every year the standard FST spots thousands of impaired drivers. You will find instructions on how to “beat the test,” but they don’t work, because you can’t use conscious effort to pass a test that works on an unconscious level. It’s not possible to fake good reflexes or the cognitive function needed to follow instructions or multitask.
The way to “beat the test” is to drive sober. Works every time.