Change the law to require rear-facing car seats for under-4s.

In Sweden between July 2006 and November 2007 not one child under the age of six was killed in a car crash. Children in Sweden sit rear facing until the age of four under the car seat safety standard LAW.
A child’s neck only needs to stretch more than a quarter of an inch before snapping/breaking.
During a frontal collision, in a forwards facing car seat, the child is flung forward. As the child's head flung/stretched forward taking on 300kg of loading within the neck at just 30mph.