Legal Question in Criminal Law in Michigan

Re: Search and seizure rights

If the officer asks you if he may search your vehicle, you may say No.

Your refusal won't keep him from the search, but it may keep the results of the search from being used against you.

Re: Search and seizure rights

You never "have to allow" an officer to search your car. If an officer asks for your consent, you can say "No".

If you do, then the officer can either get a search warrant (which can take hours, and the car might be held at the scene).

Or the officer can do a warrantless search but will have to justify in court later which exception(s) to the warrant requirement apply. Every rule has exceptions, of course, and there are some that could apply here (like plain view).