Are Field Sobriety Tests Accurate?

Our Attorney Discusses the Accuracy of Field Sobriety Tests

When you are stopped by law enforcement under suspicion of driving under the influence, including at a sobriety checkpoint, officers will conduct at least one but possibly multiple field sobriety tests. The purpose of these tests is to determine whether or not they can obtain probable cause and arrest you in order to have you take a blood or breath test. These field sobriety tests are frequently subject to scrutiny, and many people don’t realize how inaccurate they can actually be. Let’s look at three common field sobriety tests and see how accurate they actually are.

Walk-and-Turn Test

The walk-and-turn test is one of the more well-known field sobriety tests. This requires the potentially-intoxicated individual to walk heel-to-toe in a straight line (like you’re on a balance beam) while following an officer’s instructions. There are eight potential signs of impairment, which an officer may arrest you if they spot more than two. According to the NHTSA, this test is about 68% accurate in finding intoxication, however, those who struggle with balance to begin with could have a difficult time and show false positives for this test, leading to a wrongful arrest.

One-Leg Stand Test

This is a more difficult sobriety test which involves the officer having the individual stand with both feet together and arms at their sides, then lift either foot roughly six inches off the ground and hold it for 30 seconds. Should this be difficult, the driver is presumed intoxicated. The NHTSA estimates that this test is 65% accurate. However, much like the walk-and-turn test, those who struggle with balance to begin with can struggle to complete this test even while perfectly sober.

Horizontal Gaze Nystagmus Test

This is perhaps the easiest field sobriety test to administer. The officer simply holds a pen or their finger about 12-15” from the individual’s face and asks them to track it with their eyes without moving their head as they move it from side to side. An intoxicated individual’s eyes will jerk if their BAC is around 0.05, which means there is a decent chance the individual is above the legal limit.

One common theme with these tests: they are not even 70% accurate. That means statistically, 30% of people arrested because of these tests are wrongfully accused by law enforcement officers who did not establish probable cause before making their arrest. Any evidence used against those who are arrested in this way should be suppressed as soon as possible. Do you think you were wrongfully accused? Discuss your case with a Santa Rosa DUI lawyer as soon as possible and review the facts of your case.

At the Law Offices of Evan E. Zelig, P.C. we understand that police are human and not exempt from error, and we are dedicated to fighting back against your charges. We are aggressive and tireless when defending clients, and we strive to put the law on your side. Trust your case to an attorney whose excellence in the courtroom and dedication to client service has earned him selection to Super Lawyers® Rising Stars­­­^SM.