Before an Ypsilanti police officer can charge you with drunk driving, the officer must first establish probable cause to arrest you. Probable cause means that you are about to commit, in the process of committing, or have committed a crime. Police officers usually establish probable cause for drunk driving arrests by conducting field sobriety tests. The physical evidence (probable cause) taken from such tests will permit an officer to arrest you and take you into custody for further investigation.
A police officer will first pull you over if you violate a traffic law. For example, say you are swerving back-and-forth between lanes without using your blinker. The officer can pull you over for that and conduct an initial traffic violation to investigate your conduct.
Upon initial investigation, the officer will take note of certain signs that possibly indicate your impairment. The officer may ask you where you are driving from. If you say a bar, then the officer will continue to question you to determine whether or not you are possibly intoxicated. Next, the officer will request for you to perform a series of field sobriety tests.
How Field Sobriety Test Results Determine Probable Cause
Field sobriety tests are used by the officer to determine whether or not you are impaired. There are three standardized tests that indicate some level of impairment based on your performance: 1)The Walk-and-Turn Test; 2) One-Leg Stand Test; 3) The Horizontal Gaze Nystagmus Test.
If you fail the required number of indicators for the three tests, police officers can establish probable cause to arrest you. The probable cause being that they believe that you failed the tests because you are impaired (leading to the conclusion that you were previously driving under the influence of alcohol).
You may also be requested to take a preliminary breath test (PBT) prior to the arrest. If you blow above the .08% legal limit, then you will be arrested and taken into police custody for further investigation. In Michigan, an officer may rely on the results of the PBT by itself to establish probable cause to arrest you for operating while intoxicated or visibly impaired.
Under the Michigan implied consent law, you will be offered a chemical test (breath, urine or blood) after being arrested to determine your blood alcohol content (BAC). If the chemical test detects alcohol in your system above the .08% legal limit, then you may be charged with operating while visibly impaired, or operating while intoxicated, depending on your blood alcohol content level. If it is above .17%, you will be charged with High BAC (super drunk driving) and face enhanced license penalties and sentencing if convicted.
Read my article on how to challenge a drunk driving charge for more information on how to contest the probable cause element of your case.
Contact Washtenaw County drunk driving attorney Stacey Washington for a case evaluation if you have been charged with a DUI.