Michigan Child Restraint Law

Children under 4 years: restrained in a child seat
Safety advocates* recommends restraining your child in a "5-point" harness system until they are at least 40 lbs. This harness provides the best protection for your child. Infants should ride rear-facing as long as possible for the best protection in a crash. Many "convertible" car seats will allow children to ride rear-facing 30-35 lbs. (refer to mfg instructions)

Children 4 - 7 years old AND under 4 feet 9 inches: muster be secured in a child restraint
Many child seats have forward-facing harness weight limits of 40-65 lbs. (refer to mfg instructions)
Safety advocates* recommend restraining your child in a "5-point" harness system until they are at least 40 lbs. before using a booster seat. Booster seats must be used with the vehicle's lap and shoulder belt. 8 years old OR over 4 feet 9 inches can be moved out of a booster.

Children 8 - 16 years, drivers & front seat passengers: must wear a safety belt
Safety advocates* recommend that everyone in the car, regardless of seating position, should always be properly buckled up, either with appropriate car seats, booster seats or vehicle seat belts. Safety advocates* recommend children be at least 13 years old before sitting in the front seat.