Perhaps one reason why Haussmann-style diagonal boulevards never made it in Chicago is because Chicago (governed as we are by mayors, not an emperor) was unwilling to condemn and demolish enough of the old fabric. Paris demolished so much that the subdivisions could be re-platted into continuous buildable lots fronting the boulevards. In Chicago, newer diagonals like Ogden Extension never meshed into the built fabric and thus never built a constituency — the remnant lots lining them, if they were ever built, house only hot dog stands and garages.
Meanwhile, our diagonals have a way of disappearing under the grid. UIC knocked out a huge chunk of Blue Island. Clark once flowed into Rush. Parts of Kingsbury have reverted to dust over the years. Much of the Indian Boundary (Forest Preserve & Rogers) was probably never even paved before the grid arrived to then-new suburbs like West Ridge. Cottage Grove got sliced for Lake Meadows and the freeway between 24th and 33rd; a rump remnant, the saddest little street in all Chicago, ran from 24th Place (an access road along I-55) to a cul-de-sac just short of Cermak, fronted with an odd pile of abstract sculpture (the “dancing french fries”). It was lined solely with McPier parking lots, yet it had fresh bike lanes. Alas, it’s joined its fellow segments in urban renewal’s dustbin, subsumed by the colossal McCormick Place West.
Diagonal rail spurs, like the Seminary branch off the Lakewood line headed to Wrigley, also melt back into the grid when abandoned. Meanwhile, the old right angles of Lake Shore Drive’s S-curve live on as the Cancer Survivors’ Garden.