age increases awareness and the sense of self preservation. As you get older you learn not to walk out into the road, and not to put your finger in the fire, or whatever. Therefore, by definition, the young are more vulnerable.
I agree about awareness, but we are born with some degree of common sense... ...which we could argue "modern namby pamby parenting" drums out of them.
At 4yrs old, I knew not to run into roads, to look left and right, not cross where drivers/cyclists would not be able to see me well, and successfully managed to walk the mile to Dad's work after school (I went to school 5 miles from home) for 7 years without and road related incidents. By 11, as Dad had retired, I had to cycle the 5 miles - although if it was phishing down, he did sometimes go soft

I agree that driving standards in the UK are shockingly bad, but we must also give some responsibility for stupidity to the parents
and the child (speaking more general than the link above).