Locals should be able to adapt to the new rules of the road here on Albion. This one way street now has an extra lane (marked by the double yellow line) allowing bicycles to ride against the natural flow of traffic. A new sign warns motorists to watch for bicycles when making a left turn into the alley.
Imagine someone from another neighborhood or out of town visiting a friend. Its night time and you don't have the lay of the land. Driving down the street looking for parking you decide to cut through the alley for one more go around.
You hit a bicyclist who came out of nowhere. When bicycles enter the conflict from an unexpected direction accidents happen. The major reason why sidewalk bicycle riding is illegal (at least if you're over 12) is to prevent unforeseen misadventures.
(By the way you can see minor street flooding from the heavy rains that hit Chicago earlier today)