I agree what a terrible loss of a young life, it is interesting to note that no one has mentioned the driver of the car.
If as I suspect the child ran into the path of the car, just think of the driver he will have to live for the rest of his life, with the fact that he or she has killed a child.
Yes one can say "well don't you think the parents and family won't have to also"? The answer is yes tragic, one cannot imagine what they are going through "if I had done this", if we had not gone out". etc, etc.
These days, one hardly ever sees children in reins, but better still are those child restrainers, that Velcro round the child's wrist and the adult either keeps hold of the strap or fastens it to the handles of the push-chair.