Most kids start lobbying to ride in the car without a booster seat about the time they start to to experience peer pressure. But if your kid's friends are taller than he is, he may be safer in a booster, even if the rest of his crew have moved into regular seat belts. State safety regulations differ. Most use three criteria -- height, weight, age or some combination of the three -- to determine when children should graduate from the car seat stage. Even among states that use height as the only determining factor, the specific height varies.
States with a Height Requirement
While all 50 states have child restraint laws, only 25 states have laws specifying how tall a child should be before moving to an adult seat belt, according to the Insurance Institute for Highway Safety. Alaska, Arizona, California, Georgia, Hawaii, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, New Hampshire, North Dakota, Ohio, Oregon, Rhode Island, Tennessee, Texas, Utah, Washington, West Virginia and Wisconsin all have height requirements for moving to an adult seat belt or for remaining in a car seat or booster.
Height Requirements by State
The most commonly mandated height for riding in an adult seat belt is 57 inches, or 4 feet, 9 inches, according to the IIHS. All of the states listed above mandate this height, while New Hampshire uses 55 inches and Kentucky uses 50 inches as the lowest possible height for adult seat belt use.
Determining Safe Use
If your state doesn't enforce a mandatory height for the use of a booster, you can determine yourself whether or not your child is ready to ride in an adult seat belt. When your child sits on the car bench with his back against the back of the seat, his knees should bend at the edge of the seat. The shoulder belt should come across the center of his chest and shoulder. If your child slouches, leans over or can't stay properly seated for entire trip, he's not ready yet for a regular seat belt.
You might feel that your child is safer in an adult seat belt than he is without anything at all. But an adult seat belt can cause harm when worn by a child too short for it; spinal cord injuries can result. The most common cause of spinal cord injury in children is motor vehicle accidents, and improper seat belt use cause a significant percentage of these, according to an article in the 2007 issue of "The Journal of Spinal Cord Medicine." The seat belt can cause injuries to your child's neck and head, the University of Washington warns. A seat belt can also cause severe abdominal injuries if it doesn't stay low across your child's hips. Also, if a child is too small for the seat belt, he can "submarine," or slide out from underneath the restraint.