i-Size child restraint systems allow your child to travel in a rear-facing position until they are at least 15 months old. Nevertheless, this does not mean that from then on they should be in a forward-facing position. Quite the contrary, the safest way for children to travel in a vehicle is in a rear-facing child restraint system, especially until they have reached 4 years of age. Although it is advisable for them to continue doing so for as long as possible.