UN Norm R129 states that children must travel in a rear-facing position up until they exceed the age of 15 months and a height of 76 cm. However, given the current state of child restraint technology we recommend placing a car seat in the rear-facing position until the child is four years old, or as long as this is possible. The reason for this is as follows: At the beginning of their lives children generally have relatively weak neck muscles and large heads in relation to the rest of their bodies. The older they get, the stronger their neck muscles get. Additionally, the difference in size between the head and the body evens out. However, in the event of a collision in the early years of development these two factors create a large amount of strain on their necks, making car crashes statistically more dangerous for this age group. Therefore, physicians, accident researchers and consumer and health organizations recommend the transport of babies and toddlers in rear-facing child seats for as long as possible, but at least until they are 4 years old. If the child is travelling in a rear-facing position, the forces of an impact are distributed evenly over the large area of the car seat shell. The strain on the neck, head, and chest is significantly reduced, reducing the risk of injury when compared to a forward-facing car seat. Therefore, physicians, accident researchers and consumer and health organizations recommend the transport of babies and toddlers in rear-facing child seats for as long as possible.