The Science Behind Field Sobriety Tests

Field sobriety tests are often presented as a reliable tool used by law enforcement to identify impaired drivers. These roadside exercises are intended to assess coordination, balance, and the ability to follow instructions — factors believed to be impaired by alcohol or drugs. However, these tests are not as objective or scientific as they might seem. Many drivers are surprised to learn that performance on these tests can be influenced by more than just intoxication as our Hartford, CT DUI lawyer can share.

At Brown Paindiris & Scott, LLP, we’ve handled DUI cases where field sobriety tests were used as primary evidence. It’s important to understand that these tests are based more on observation and officer judgment than on measurable science. The results are often subjective, and many people fail these tests for reasons unrelated to substance use. The tests play a very important role in cases, as a young man learned when he received an eighteen month prison sentence.

Types Of Tests And What They Claim To Measure

Field sobriety tests typically include three main exercises: the horizontal gaze nystagmus test, the walk-and-turn test, and the one-leg stand. These are standardized by the National Highway Traffic Safety Administration (NHTSA), but their accuracy still varies. The horizontal gaze nystagmus test looks for involuntary eye movement, while the walk-and-turn and one-leg stand focus on balance and coordination.

These tests assume that everyone has the same physical ability, which is rarely the case. Factors such as age, medical conditions, anxiety, and even the type of footwear can impact performance. This can lead to unfair assessments of impairment. You may be familiar with the fact that even food eaten before the test can affect it such as poppy seeds.

Subjective Interpretation Can Affect Outcomes

One of the biggest concerns with field sobriety testing is the level of subjectivity involved. Officers are trained to look for specific “clues” of impairment, but the determination is ultimately based on their judgment. What might seem like poor balance or inability to follow instructions could actually be due to nerves, fatigue, or a non-visible medical condition.

For example, someone with inner ear issues may struggle with balance, and someone who is nervous or unfamiliar with the situation might not perform the steps with confidence. This doesn’t mean they’re impaired, but it can still lead to an arrest if the officer interprets the signs that way.

Field Sobriety Tests Are Not Always Conducted Properly

Another issue is the setting in which the tests are administered. Roadside conditions are often less than ideal — uneven pavement, poor lighting, traffic noise, or bad weather can all interfere with a person’s ability to perform well. Even something as basic as being asked to take the test in dress shoes or boots can impact the result.

If the test is not given according to the proper protocol, or if the officer fails to consider external factors, the results may be questionable. This is why challenging the accuracy and fairness of these tests is a key part of many DUI defenses.

Why Legal Representation Matters In DUI Cases

Challenging field sobriety test results takes experience and attention to detail. At Brown Paindiris & Scott, LLP, we’ve built a strong reputation for effective DUI defense strategies. Our firm includes a Rated Attorney as Lead Counsel. We have also received a peer rating for the Highest Level of Professional Excellence from Martindale-Hubbell. We focus on identifying weaknesses in the state’s case and building strong defenses tailored to our clients’ situations. We’re here to help you understand your rights and pursue the best outcome possible. No family should ever have to know the pain of losing a family member to a drunk driver or an incorrectly administered test. If you’re facing DUI charges based on field sobriety tests, contact us today to discuss your situation and learn how we can support you.