Are field sobriety tests always accurate?

On Behalf of | Oct 18, 2023 | Drunk Driving |

If a police officer suspects someone of drunk driving, they typically need evidence beyond their personal suspicions to arrest that driver. One of the first ways an officer can screen someone for intoxication is through a series of field sobriety tests.

Field sobriety tests focus on someone’s physical ability and cognition. The results of a field sobriety test might justify a police officer’s decision to request a chemical breath test or to arrest someone for drunk driving. Some people assume that if they fail field sobriety tests, then they have no chance of defending against their pending charges. What they may not realize is that field sobriety tests aren’t universally accurate.

People fail these tests for all kinds of reasons

There are three standardized field sobriety tests that officers typically perform when they suspect someone of intoxication while driving. The one-leg stand test looks at someone’s balance and coordination. The walk-and-turn test also looks at someone’s ability to follow instructions and to maintain their balance, as well as an even gate while walking.

Sometimes, officers add a mental component to these tests by having someone recite the alphabet or repeat certain words. Finally, officers perform the horizontal gaze nystagmus test to observe whether someone has an involuntary muscle spasm that indicates they may be under the influence of alcohol.

While these tests are good screening tools, they do not produce conclusive evidence of intoxication. A variety of different health issues could lead to someone failing field sobriety tests. People may have conditions that affect their musculature. They may have issues with coordination or their fine motor skills that do not prevent them from driving but affect their test performance.

There might even be mental health conditions, like anxiety or post-traumatic stress disorder, that can impact someone’s performance on a field sobriety test. Particularly if someone has a medical condition that affects their motor function or issues with nervousness, the results of a field sobriety test may not be as authoritative as police officers and prosecutors may like to claim.

In some cases, providing medical evidence to undermine field sobriety test results can be part of a successful defense strategy. Ultimately, seeking legal guidance and better understanding the limits of roadside sobriety testing may help people better respond to pending criminal charges.