Rear Facing Car Seats

Starting January 1, 2017 children are required to remain in a rear facing car seat "unless the child weighs 40 or more pounds OR is 40 or more inches tall" in the State of California.  The average child will not reach 40 lbs/40 inches tall until they are 4 years old. The rear facing position is five times safer than forward facing because it provides more protection for the child's head, neck and spinal cord.  

Babies are not miniature adults. Babies have spinal cords that are not fully fused at birth. When bodies are still developing they are more vulnerable to injuries. The infants spinal cord is connected with cartilage rather the fused bone. This means that in an accident when an adult would get slight whiplash a child could have their spinal cord detach. 

When using a rear facing car seat the harness should always be at or below the shoulders. The chest clip should always be at armpit level. 

The harness should always be tight enough that you can not pinch any slack at the shoulders. 

Remember that when installing a car seat you should never have more than one inch of movement at the belt path after the installation is complete.

Vertebrae age 1 and 6
Photo Credit: White, T. Human Osteology, 2000

According to a study published in the Association for the Advancement of Automotive Medicine
 the first station to close is the C3 vertebrae, the second is the axis and the third is the atlas. 

  • 50% probability that the primary closure of the C3 is complete at age 2 and the secondary at age 3. 
  • 50% probability that the primary closure of the axis is complete at age 5 and the secondary at age 6.
  • 50% probability that the primary closure of the atlas is complete at age 7 and the secondary at age 8 (Yoganandan, Pintar, Lew, Rao & Rangarajan, 2011).

According to NHTSA (the national highway traffic safety association) spokesperson Gordon Trowbridge "front end collisions account for 43 percent of injuries to children in car seats. Side-impact crashes account for about 33 percent and rear-end crashes 9 percent." This data is significant because rear end crashes are frequently at low speeds and the passengers are generally not injured significantly. Passengers are more likely to be in a frontal impact collision, and the impact is likely more severe. No matter what type of crash it is safest for your child to be rear facing until they reach the height and weight limit of their car seat.