You can carry a loaded firearm anywhere, anytime, anyway in the U.S. but, you have to have a lot of money to buy a Great Lawyer to defend your 2nd Amendment right to Keep and Bear Arms which shall not be Infringed" Now to answer your Question in the realm of the Current Printed Laws (Which most are Unconstitutional) one stands out...Sections 2 (MCL 28.422) and 9 (MCL 28.429). The only way to carry a loaded fire arm in a Vehicle without a CPL is to carry a Black Powder Pistol, It does not fall under the the CPL requirements. That is to say you can Purchase a BP Pistol at age 18 from a FFL dealer, no purchase permit is required, and as the law is written, you do not need a CPL to transport it, or carry it. The state and Feds do not recognize it as a Fire Arm. Since it is not considered a Firearm it does not fall under the CPL laws, and can be carried loaded in a Car/Truck with out a CPL. Now that being said some here and almost all LEO' and Lawyers will say the last part is grey so research it for yourself.