A field sobriety test (FST) is a physical task that a police officer asks a driver to perform so that the officer can assess whether or not the motorist in question is impaired. The results of a field test can serve as evidence of impairment, although it cannot serve as proof of impairment on its own. Oftentimes, field sobriety tests are simply used as probable cause for a breath test.
There are three main FSTs that are used, which are as follows:
- The horizontal gaze nystagmus test, which looks at how the eye moves as it tracks an object.
- The one-leg stand test, that tests balance.
- The walk-and-turn test, which is aimed at balance, coordination and following directions.
The idea behind these tests is that someone who is impaired will probably fail them, while someone who is sober should be able to pass them easily. But is that actually true? In reality, there are many ways that sober people can fail these tests.
Sickness or fatigue
For example, what if someone is feeling fatigued after a sporting event or a long day at work? Or what if they’re just feeling sick because they’ve come down with a virus that’s going around? This could make it much harder for them to concentrate on the task that they’ve been asked to accomplish, and they may be more likely to stumble or make mistakes. But that doesn’t mean that they aren’t sober.
Injuries and disabilities
Additionally, field sobriety tests assume that everyone is in optimal physical condition. But what if they’ve recently suffered an injury or they live with a lifelong disability? Either of those things could make it far harder for them to complete tasks effectively, even though they are sober.
Finally, field sobriety tests are not performed in a vacuum. There are many factors that can influence the outcome of a test at any given moment. For instance, a person may have no trouble passing the walk-and-turn test if they were inside a well-lit room, where they could clearly see what they were doing. But they may be taking the test in the dark, in the rain, or in other adverse weather conditions, and doing it on the side of the road as part of a very stressful situation. Mistakes are simply more likely under such conditions.
As can be seen, field sobriety tests are perhaps not as accurate or dependable as many people assume. For this reason, and a host of others, those who are facing allegations of impaired driving need to know what legal defense options they have available to them by seeking legal guidance right away.