In order to conduct a traffic stop, an officer must have “reasonable suspicion” that the individual operating the vehicle is intoxicated. According to the State of Wisconsin OWI Enforcement Manual, reasonable suspicion is defined as, “anything that would lead a reasonable officer to believe that a person may be under the influence”.
Signs considered evidence to gather reasonable suspicion include road violations such as speeding, driving too slowly, or swerving.
Reasonable suspicion is enough to make a traffic stop, but it is not enough to make an OWI arrest. In the case of an arrest, there must be “probable cause”. Field sobriety tests (FST) are one of the methods administered during a traffic stop in order for an officer to search for signs of impairment and conclude probable cause. Field sobriety tests (FST) are voluntary. However, the refusal to participate in such tests could simply aid an officer in establishing probable cause for an arrest.
What are the types of field sobriety tests administered when pulled over for an OWI?
There are three standardized field sobriety tests administered during a drunk-driving stop.
Horizontal Gaze Nystagmus Test
Consumption of alcohol elevates the difficulty for the eyes to track objects quickly, causing jerking and oscillating movements. In order to test if the suspect’s eyes oscillate or jerk, the Horizontal Gaze Nystagmus test is administered by an officer holding an object. The object is placed 12-15 inches away from the suspect’s nose, and is moved from side to side. If the officer observes at least four clues of intoxication, this test establishes probable cause to make an arrest.
The officer first demonstrates how the test is done, instructing the suspect to take nine heel-to-toe steps in a straight line, counting each step, with their arms by their side, while watching their feet. The suspect is then instructed to turn after the nine steps, and to repeat the stepping motion until they are instructed to stop. The officer searches for signs of intoxication such as failing to step in a straight line or stopping while walking.
One-Leg Stand Test
The suspect stands with their heels together, with the instruction to raise one leg six inches off of the ground with their arms by their side. They are then told to switch legs and count out loud, in thousands. The officer searches for signs of the test proving difficult for the individual, such as loss of balance, or hopping.
If you have been arrested on an OWI-related charge, contact Stroud, Willink & Howard Criminal Defense Group LLC immediately, as our attorneys are trained in the science of OWI evidence collection. Our specialized training puts us in the ideal position to defend your case. With the state holding the burden of proving you were intoxicated with operating, our detailed research of facts surrounding your OWI arrest will serve in powerfully challenging your charges.