As our autos team writes, this is National Child Passenger Safety Week.
 
That’s not to say that the safest possible travel shouldn’t be the goal for children every week of the year. Fortunately, more children under the age of one are placed in child safety seats than ever. And booster seats, which are designed to protect older children, are now required in 47 states and the District of Columbia. Only Arizona, Florida and South Dakota haven’t yet enacted booster-seat requirements.
 
While all 50 states require car seats for the youngest occupants—those under one—laws governing age, height and weight parameters for booster seats vary from state to state.  So when you’re driving in Maine with your 70-pound seven year old, she must be in a booster seat or safety system. But cross the border into New Hampshire and she outgrew any such requirements when she turned six.

Kids come in all shapes and sizes. Though a height of 4 feet nine inches is a better indicator than weight and age of when adult seat belts are more likely to fit, no two kids are alike. To determine whether a child needs a booster seat, parents should ask themselves four questions. With the child seated in the car against the seat back:

1. Do the child's knees bend comfortably at the edge of the auto seat?
2. Does the belt cross the shoulder between the neck and arm
3. Is the lap belt as low as possible, touching the thighs?
4. Can the child stay seated like this for the whole trip?

If any of the answers are no, the child should be riding in a booster seat.

Our take: We think the differing laws are needlessly complicated for adults and risky for children. There should be a single federal law to protect all children riding in cars. We think boosters seats should be required for all children up to 4 feet 9 inches, a point at which adult belts in most vehicles fit correctly.