Police officer conducting horizontal gaze nystagmus test on woman with car in the background

Are Traffic Sobriety Tests Too Hard?

Have you ever heard of police asking someone to stand on one leg or walk a line like a penguin? If so, that person was probably describing a field sobriety test. These tests have been around for over 60 years, but they’re often ineffective at determining whether someone is safe to drive, even under laboratory conditions, and often return false positives. That raises the question, are traffic sobriety tests too hard?

The Anxiety of a Traffic Sobriety Test

One of the biggest challenges in any of these tests is the mere presence of a police officer. Even though police are employed to keep us safe, it’s not uncommon to feel nervous when you see those flashing lights in your rearview mirror. On a cold night, when cars are passing you at 60 MPH, and the officer sternly asks you to get out of the vehicle, that anxiety can get the best of you, even when you’ve done nothing wrong.

Those combined factors may explain why many people are already nervous when they step out of the car, effectively making it more difficult to follow a long list of instructions.

Types of Tests

The three most common field sobriety tests are the “Horizontal Gaze Nystagmus (HGN),” “one-leg stand (OLS),” and the “Walk and Turn (W&T).” Both of these tests are highly dependent on your ability to remember information and your natural balance. Let’s take a closer look at each.

Horizontal Gaze Nystagmus

In this test, an officer puts a stimulus (usually a pen) in front of your eyes. They’re looking for a difference in pupil size, equal tracking with both eyes, and smooth tracking that follows the stimuli as it moves from your left to your right.

There are a few problems with this test. First, your pupil size is determined by the light source. Your eyes dilate in the dark and contract in bright light. If you get out of your car and your left eye sees police lights, but the officer blocks the view of your right eye, you’ll likely have different-sized pupils.

At the same time, other stimuli (such as passing cars or the police lights) can break your attention and cause you to lose focus, potentially causing you to fail the test.

The One-Leg Stand

For this test, a police officer will ask you to raise one foot off the ground, put your arms out, and then slowly count to 30. The officer will judge your performance based on how your arms sway, whether you hop in place and whether you put your foot down.

The immediate problem with the OLS test is that it’s highly dependent on your dexterity. Try the test for yourself and see how much you wobble. If you don’t balance the weight on your foot just right, you’ll shake until you find your center of gravity.

Walk and Turn

The W&T test is arguably the most notorious traffic sobriety test because it is both complicated and has the highest fail rate. Here’s why.

Walk in a straight line, heel to toe, for ten steps. Turn around and walk back. Keep your arms at your side the whole time. Count each step aloud. Don’t stop until you’re done. Make sure your feet stay on the white line.

Sometimes the instructions are only stated once and their order matters. The more instructions there are, the more likely you are to misremember what you need to do. At the same time, trying to remember to walk a certain way, keep your arms at your side, and then keep your feet on the line can be confusing because you’re trying to organize the instructions for each part of your body.

The W&T test returns a false positive 1-in-3 times, and those are for studies done in an auditorium or an office, not on a busy highway in the middle of the night.

It’s also possible that grading is subjective. Studies have found that those viewing the same traffic sobriety test on video each had a different opinion on whether the subject was intoxicated. That’s especially alarming when you consider that 25% of all sobriety tests return a false positive.

Just Say No

All three of these tests have a high fail rate, even in the best circumstances. Remember that you have the right to refuse a field sobriety test. However, you must remember that you won’t usually be asked whether you will submit to the test. Instead, you’ll be told that a test will be administered and instructions will then be provided.

With a very high rate of false positives, it may be better to avoid the test altogether, even if you’re completely sober. These tests could potentially be used against you in court, even if you perform perfectly. Simply put, there is no benefit to taking a field sobriety test.

Only agree to what is required by law, and keep comments to a minimum until you’ve had a chance to speak to your attorney.

If you’re facing DUI charges, it’s crucial you have legal representation. To speak with an experienced Murfreesboro criminal defense attorney from Parkerson Santel, PLLC, call (615) 987-0268 or send us an email.

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