Kathy Carnes of Coldwater buckles her son, Hunter, 5, into a booster seat inside the family's van. Hunter weighs 39 pounds and would have been able to use a standard vehicle seat belt after reaching 40 pounds, according to current law. However, new legislature goes into effect April 1 that requires all children use a booster seat until age 8 and 4-feet, 9-inches tall.