Johnson Avenue in western Cedar Rapids carried the Lincoln Highway, and then US 30, until 1940. Back then, it was outside the city. Nowadays, it’s a minor urban arterial that’s about to be reduced in capacity.
The city of Cedar Rapids is using Johnson Avenue as a guinea pig in a “complete streets” program. According to the Gazette, the street will be reduced to two lanes with bike lanes and have roundabouts at Wiley Boulevard and Jacolyn Drive. There’s a cost savings in the change; the Wiley roundabout will be $91,000 less than having a stoplight, the story says.
There are other roads in the city where one or both of those things are going to be done to them, too (see list at link).
As far as I know, this is the first second time roundabouts have been installed on any era of Lincoln Highway alignment in Iowa.
UPDATE 4/16: Marion’s new roundabouts on either end of downtown put one on the 1913 route (now part of a loop) — the west one at 7th Avenue and 7th Street.