I never drive by that area of road and don't think about it. If there are cars parked, especially big cars and things like a bus, there is a chance of a kid or dog appearing from nowhere in your path.
I'm glad the kid was ok, but the hair goes up on the back of my neck for you. Had the worst happened, through no fault of your own, you'd be a different person because of the weight of the unnecessary guilt.
I'm far from perfect and I know all of my children and siblings and other relatives I've taught drive are not perfect either. But, as my father taught me, a gun is always treated as loaded, and electric wires are always treated as hot, I taught that from behind any parked car or obstruction, a child could come and someday will come. And to be prepared for it.
There's a corner on Beacon Hill Drive and Lil' Stash was taking me down the hill one day. I asked him before he got to the corner, "Do you know why there is no sign with the 'suggested speed' going around this corner?"
"No," was the obvious response.
"Because the only safe speed is zero. Remember that on wet or icy days. This corner isn't safe in dry conditions."
So far he hasn't ended up across the many-time-replaced barracade, yet.