mindstalk | Chicago superblocks (Reply)

(I'd swear I've written this somewhere before, but I see no evidence of it anywhere.)

I've talked before about superblocks. There's the Barcelona model, of 3x3 blocks with one way loops so cars legally can't go through. (Disadvantage: may be complicated to scale.) I've privately imagined various other configurations, like putting diagonal diverters in so that cars have two-way access but physically can't go through the area, dividing the superblock into four half-diamond quadrants. (Possible disadvantage, access requires entering from the correct side.)

But one thing I realized recently was that where I grew up in Chicago almost has superblocks by accident. 4x4 blocks, 3 residential (side) streets between two main ones. No deliberate traffic calming or prevention at the time. So you could easily zoom your car down the side street. But then what, how will you cross the main street? No light, no stop sign (well, stop sign for you, not for the cross traffic.) So you get to wait for a double break in traffic before you can cross. That's annoying! Possibly annoying enough to prevent rat-running, as such driving through residential areas is called. Voila, a quiet area.

Of course, it's just as annoying to cross on foot or bike, which is bad, and thus why this isn't actually a superblock (at least in the modern Barcelona-inspired sense.) But we can fix that! My Chicago neighborhood has been putting in yield signs (well, not official red and white yield signs, but the yellow "pedestrians here" signs that people tend to think of as yield signs). One can do better, with HAWK beacons or other "beg button" signals, that will stop cross traffic on request (but the button is only for walkers and bikers, haha!) So drivers still have to wait for a break, while pedestrians can make a break.

And relatedly, you can put a permeable barrier in the median of the cross street, that will physically block cars from crossing. Like this. Well, kind of like that: it's flexposts and with a wide walk area, so someone could drive through, but there's at least a strong signal that they're not supposed to. Cedar only has that where 9th crosses it, as 9th is one of Berkeley's "bike boulevards" with various measures like that, but you could treat all the main street medians like that, block after block. So cars can get in, but not through. Woo!