If law enforcement suspects you of drunk driving, they might ask you to perform what are called field sobriety tests. These tests exist to help the police determine if there’s enough evidence to ask you to take a preliminary breath test. These tests usually happen by the side of the road before an arrest. Although law enforcement officers usually perform many drunk driving investigations during their career, it is one of the most complicated types of investigations that law enforcement performs. An experienced Grand Traverse drunk driving attorney can help you determine if law enforcement made errors in their investigation.

Standardized v. Non-Standardized Tests

In the 1970s and 1980s, the National Highway Traffic Safety Administration (NHTSA) set out to study what field sobriety tests actually predict intoxication with any measure of scientific accuracy. The result of those tests was that three tests used together by a trained investigator can reasonably predict a person’s levels of intoxication. These tests are the horizontal gaze nystagmus, the walk and turn test and the one leg stand.

Sometimes, law enforcement officers prefer to defer to old habits even when these habits are not scientifically sound. That means that they might ask you to touch your finger to your nose, say your ABCs or perform finger dexterity tests. If they do, your DUI attorney Traverse City can point out to the jury that these tests aren’t helpful for determining your level of intoxication.

The Standardized Tests

The horizontal gaze nystagmus (HGN) test is a test that allows the police officer to look at jerking movements in your eyes. You keep your eyes on a moving pencil or the officer’s finger. If your eyes jerk involuntarily as you look to a corner, it’s a sign of intoxication.

The walk and turn test involves taking several heel-to-toe steps on a line, turning and taking several steps back the other way. The officer asks you to keep your arms at your side and count the steps as you walk. The officer looks for balance as well as for your ability to follow instructions. If you’re asked to do this test, a drunk driving attorney Traverse City can help evaluate your case to determine law enforcement followed the proper procedures.

The one-leg stand is the third standardized field sobriety test. It involves holding one leg in the air as you keep your arms by your sides. You hold your foot approximately six inches off the ground and count out loud. Again, the officer looks for balance as well as for the person’s ability to follow instructions.

Other Signs of Intoxication

When making a decision of whether to arrest someone for drunk driving, law enforcement takes other observations into account. They look for whether a driver has bloodshot or glassy eyes. They try to detect an odor of intoxicants. If the driver looks unsteady on their feet, law enforcement may take this into account as well.

A person that’s under investigation for drunk driving doesn’t have to answer law enforcement’s questions. However, if a person admits to drinking alcohol or using drugs before driving, the police are going to use these admissions against the driver. If the police find alcohol or empty alcohol containers in the car, this is also going to weigh against the driver. If you’re facing drunk driving charges, it’s important to work with a skilled and experienced Traverse city drunk driving attorney to ensure that law enforcement followed proper protocol when they investigated the case. If you’re facing criminal charges in Traverse City, Grand Traverse or anywhere in Northern Michigan, please contact us today.