It comes down to this: Speed and inattention kill, and our society routinely encourages both, whether by design, selfishness or neglect.
If you don't walk or bike in these settings, you simply can't ever understand it. Any city official or engineer who believes otherwise is delusional.
By extension, designing purported "solutions" in the absence of understanding constitutes a fool's errand.
The Everday Surrealism of Automobile Violence, by Bill Lindeke (Twin City Sidewalks)
... The only real conclusion here is that the embedded violence of the automobile is something we take for granted. Cars are deadly, and we’ve surrounded ourselves with them. At the flick of a foot, any drugged-up maniac can kill just anyone at any time, even someone minding his own business riding the city bus down Dale Street at seven miles per hour. Designing a society around the automobile is not only wasteful of our energy and collective resources, not only alienates us from each other and feeds our most misanthropic feelings, but it must result in senseless death. This is the only outcome when our cities practically require everyone to wield a weapon every day.