More recent statistics show that over twice as many children were killed on the roads in 2014 compared to 2013.
Source - Road Safety Authority
In a crash at just 50km/h, a child not wearing a seatbelt or using a child car seat would be thrown forward with a force 30 to 60 times their body weight. They would be thrown about inside the vehicle, injuring themselves and, quite possibly, seriously injuring or even killing other people inside the vehicle. They are also likely to be ejected from the car through one of the windows.