In Michigan, there’s no law that specifically requires you to roll your window all the way down during a traffic stop.
What is required:
You must comply with lawful orders from police (such as providing your license, registration, and proof of insurance).
You have to make your documents and yourself reasonably accessible to the officer.
Many drivers will roll the window down fully to make things easier, but technically, you only need to roll it down enough to communicate clearly and hand over documents.
That said, if an officer feels that your partially opened window is interfering with communication, safety, or their ability to verify your identity, they may order you to roll it down further. Not following such a direct order could escalate the stop.
👉 In short: No, you don’t have to roll it all the way down by default, but you do need to roll it down enough to comply with requests and ensure clear communication.