There’s a great deal of confusion surrounding field sobriety tests. For example, many wonder if they have a legal obligation to take these tests after being pulled over and suspected of drunk driving. People also wonder what legal rights they have in these scenarios and what they should say to police. This article covers the topic of field sobriety tests in Michigan and provides answers to many of these basic questions.
What Are Field Sobriety Test?
Before answering some of these questions, let’s start with the basics and provide a brief overview on the subject.
Field Sobriety Tests (FSTs) are standardized tests used by law enforcement to determine whether or not someone is under the influence of alcohol or drugs while operating a motor vehicle. These FSTs are a method of gathering evidence and obtaining probable cause for an arrest if someone’s blood alcohol content (BAC) is above the legal limit.
You’ve most likely witnessed these tests being conducted on the side of the road or on TV. One of the most common types of FST’s involves an individual who’s suspected of drunk driving blowing into a Preliminary Breath Test (PBT) which is commonly referred to as simply as a “Breathalyzer.”
Types of Field Sobriety Tests
The police use a battery of testing methods to gather evidence and obtain probable cause for a DUI arrest. You can see an example of what police are looking for while conducting these tests on the Michigan State Police SFST Scoring Sheet.
Below are some of the most common types of field sobriety tests in Michigan.
Preliminary Breath Test (PBT) – Preliminary Breath Test’s measure Blood Alcohol Content (BAC) by having the suspect blow into a small hand-held device commonly referred to as a “breathalyzer.” The device provides police with a numeric reading which is used to ascertain the level of impairment. In Michigan, the legal limit is .08, so if someone is at, or above this limit the police will have the necessary probable cause to make an arrest.
Horizontal Gaze Nystagmus Test (HGN) – The HGN field sobriety test involves law enforcement observing a suspect’s eyes to measure the level of potential impairment. Nystagmus is actually a medical term used to describe the involuntary movement of the eyeballs. In this test, the officer will typically use an object such as a pen and ask the suspect to slowly follow it with their eyes as they move side-to-side.
One Leg Stand – Simply put, the “one leg stand” test involves an officer asking a suspect to stand on one leg so that the officer can observe their balance. Here’s a list of standardized clues used by police to gather probable cause for an arrest. This list is taken directly from the SFST scoring sheet used by Michigan State Police.