There is a really good reason to keep kids in the back seat as long as possible. Until a child has a mature skeleton, the protection provided by seat belt restraint is not as optimal as an adult.

Most parents are allowing their children to sit in the front seat because they don’t understand why the back-seat-until-13 recommendation exists.

So, how is a seat belt in back, better than a seat belt in front? Seat belts are designed to keep an adult safe during a motor vehicle collision (MVC). The position of the lap belt is specifically designed to ride over the lower part of an adult hip bone. The shoulder belt is designed to securely cover the breast bone. The combination of these two belts protects us during a MVC by keeping bodies in the car from being ejected, and by slowing the rate that bodies come to a complete stop.

The belts use two of the strongest areas of our skeleton to do this – the rib cage and hips. Although some children under the age of 13 may seem as big as an adult on the outside, they are not an adult on the inside.

The hip bones are not fully developed until 12-13 years of age. It is the pointy, angled area on the front of developed hips that keeps a lap belt low and snug. On a child with rounded, relatively soft hips, the belt will “ride up” onto the abdominal cavity during an MVC – even if the belt starts in the right place! This shift of the lap belt’s proper position increases the risk of injury to abdominal organs.

The development of the breast bone (sternum) is even more inconsistent. Mature, stable breast bones can be seen as early as 11 years old. Full development, however, can be seen as late as 17 years old. Without a mature skeleton, a child is at increased risk of injury and death in the event of a MVC.

The back seat position provides additional protection because it is furthest away from three things responsible for most injuries: the windshield, the dashboard, and the airbag.

The data clearly shows this is a safer way to travel:
• Buckling up in the back seat decreases the risk of death by one-third.
• Passengers in the front seat are at greatest risk of injuries.
• Rear-seated passengers have 60% better protection in side impact collisions.
• Studies repeatedly suggest the risk of injury becomes equal to those of an adult person after the age of 13 years.

When you know the physiology and you see the statistics, the recommendation becomes easier to understand. Use this information to make the best decisions for your own children’s car travel, and encourage other parents to give the tweens the back seat for a while longer.