[scarlson]

The cities would have been responsible for building sidewalks to the bridge. If you look around where the bridge is on modern maps you'll see that a lot of the residential area on the North side of the bridge (Richfield) just doesn't have sidewalks.

[tylervigen]

It's even weirder than that! Residents of Richfield at the time saw the lack of sidewalks as a feature, not a bug. They wanted to distinguish themselves from Minneapolis, so they protested the building of sidewalks because "how would people know we are a suburb if we have sidewalks?" (This is a real quote from a real, very politically active resident at the time. Seriously.)

Context: I wrote the article linked in the OP.