Whole Foods recently opened its new, enormous Chicago store at 1550 N. Kingsbury St., on an old brownfield lot. The old industrial infrastructure surrounding the site—including a still-active spur line railway running down the center of Kingsbury St.—still has some, ah, quirks from the days before tens of thousands of shoppers went there every week. The intersection of Weed, Kingsbury, and Sheffield, for example, goes off in five directions, not including the three parking entrances:
The store occupies the vacant patch in the lower-left quadrant of this image from Google Maps. The store parking lot has entrances near where Weed meets the river, and also near the "A" marking on this photo. North Ave., Clybourn St., and Halsted St., the largest streets in the area, are just beyond the top and right sides.
So a lot of traffic now goes past that intersection. Not just cars, either; with two major bus routes and a Red Line station right there, the store attracts lots of pedestrians. (Parker and I often go there, for example; it's about 3 km from home, so the round-trip makes for a good hour of walking.)
Until this week, the intersection only had two stop signs, one on the southbound Kingsbury corner, the other on the westbound Weed corner.
Tom Vanderbilt, author of Traffic, and Andres Duany, Elizabeth Plater-Zyberk, and Jeff Speck, the authors of Suburban Nation, would argue that this is probably less dangerous than it sounds. Everyone approaching the intersection instantly realizes that he has no idea where anyone is coming from or going to, no idea who's going to stop or go, and no idea where the guy with the dog will choose to cross. Consequently, he slows down and starts paying attention.
I am surprised that it took two months for the city to respond. Clearly we can't have people thinking for themselves at a dangerous intersection. So now the intersection has stop signs all around. My prediction: drivers will pay less attention, except to struggle with remembering who goes first when you all arrive at an intersection simultaneously, with no effect at all on accident rates. As long as Parker and I can get across the street, we're fine.
 In Illinois, there is no rule. Probably you should observe the majority rule and wait for the person to your left to go before you.