Standardized field sobriety tests were developed in the 1970s. Even at the time, the science behind them was known to be a little bit unreliable. Unfortunately, says NY traffic ticket lawyer Zev Goldstein, they continue to be used across the country, in many cases as part of the evidence to convict otherwise responsible individuals. It is crucial, therefore, that lawyers attempting to fight a drunk driving charge are able to fully understand field sobriety tests, their roots, and why they might not be as reliable as many people believe.
Field Sobriety Tests Are Voluntary
Drivers who are stopped for field sobriety tests don’t have to take them. Taking a field sobriety test is voluntary. In many cases, however, defendants may not even realize that they’ve given permission for the Horizontal Gaze Nystagmus test—or that the officer has likely already decided on the verdict before the test is conducted.
Three “Reliable” Tests
There are a variety of sobriety tests that are actually used in the field. Many people have been asked to touch their noses, recite the alphabet backwards, or perform a variety of other tasks. However, there are only three tests that are even somewhat reliable in determining whether or not a subject is inebriated:
The Horizontal Gaze Nystagmus test requires the officer to evaluate the way the individual’s eyes move in response to outside stimulus. Typically, they’re asked to follow a pen or a small light while the officer looks for eye movements that are jerky, an inability to follow the pen, and when the eye begins to jerk.
The One Leg Stand is exactly what it sounds like. The individual being tested must raise one leg off the ground, look at it, and hold the position for thirty seconds while counting by thousands.
The Walk and Turn test requires the subject to take heel to toe steps on a straight line, then turn and repeat it in the other direction.
Even if all three tests are used correctly – that is, conducted exactly according to the instructions and combined – they only have an 83% accuracy rate in predicting a BAC of more than 0.10. That allows for a 17% deviation based purely on other circumstances and doesn’t allow for tests that have been performed incorrectly.
Planting Seeds of Doubt
It’s the lawyer’s job to convince the jury from the very beginning of the trial that these tests aren’t as accurate as most officers would like for them to believe. Start with the knowledge that 98% of officers conducting the tests do them wrong. They don’t perform them under controlled circumstances: the ground at the side of the road is often uneven, and wind, the placement of the sun, and a variety of other conditions can impact the results. These seeds of doubt should be planted from the very beginning so that by the end of the trial, the jurors are already convinced of the defendant’s innocence.
Evaluating the HGN Test
The HGN test is the most misunderstood of the three tests and the one that it is most difficult to properly evaluate. Many officers don’t even know how to correctly administer it: they may move the pen too fast, hold it for too short a period of time, or fail to correctly identify the eye movements that can indicate intoxication. They may also fail to properly identify a 45 degree angle—something that you can ask the officer to do on the stand. Check the video and time it: if the test takes less than a minute, the officer has done something improperly. All of these steps are critical to ensuring that the client isn’t facing a DUI charge through no fault of their own.
In many cases, standardized field sobriety tests are designed primarily to incriminate, not to prove anything. By the time they pull over the driver, many officers have already made their decision. Once the case goes to court, however, it’s the lawyer’s job to ensure that those tests are not used to incorrectly convict someone who isn’t guilty.