According to the booster seat laws in most US states children who are under 8 years old must ride in a booster seat. To be safe keep your child in a forward facing car seat with a harness as long as you can until they are at least 5 years old at least 40 pounds and able to sit in a booster for. Michigan Car Seat Laws Updated 2022 Greatest Speakers When Can A Child Switch To Booster Seat In Michigan. . Even if your child is 8 and it is legal for them to stop using a booster seat if they are under 4 feet 9 inches tall you should continue to use a booster seat to keep your child safe. According to Michigan car seat law Michigans child booster seat law requires children to be properly buckled in a car. Make sure any booster seat you use is installed correctly. If your booster seat is approved to UN R129 you have to stop using the seat once the maximum height has been reached which is 150 cm based on the regulation. Only severa...