November 4, 2019: From the Lincoln Highway in 2011 to the Jefferson Highway in 2019, Iowa’s scenic and historic byways received a more uniform, more visible signing scheme in the 2010s.
Since the Second Great Decommissioning and completion of four-lane corridors that had been planned out in some form since the late 1960s, the Iowa highway system on paper was between mostly dormant and low-level active for the 2010s. These changes do not cover the massive interstate projects in Council Bluffs and Sioux City, which totally reshaped how traffic gets through but did little map-wise.
- US 20 was completed to four lanes across Iowa six decades after proposals for its existence came alive. It opened in three segments: US 169 to Moorland, Moorland to Early, and Early to Moville, joining concrete that had been there since 1958.
- That caused the first reroute for US 71 since the Storm Lake bypass, the death of IA 196, and the creation of the highest-signed 400-series number in Iowa, 471. (I’d have preferred it as an extension of IA 39.) Three other numbers — 98, 152, and 370 — also vanished from the state map.
- New border bridges opened for US 275/IA 92, US 34, and US 52/IA 64, and IA 86 at the IA/MN line was tweaked.
- Three routes were moved to existing roads around cities: US 6 to avoid Broadway in Council Bluffs (but I think it should be totally flipped with US 275 in Omaha), IA 92 around Muscatine, and US 61 around Davenport. The latter led to a complete four-lane corridor for the route from Dubuque to Grandview after a short four-lane segment in Louisa County opened.
- The US 61 Fort Madison bypass opened, causing IA 2‘s east end to move from the Mississippi River rail bridge to the west side of the city and also creating a continuous four-lane 61 from the north side of Keokuk to Burlington.
- IA 100 was extended around the northwest side of Cedar Rapids.
- From January 2010 to July 2019, there were 11 endpoints moved (including IA 100’s west end twice), two new endpoints created, two secret routes deleted (IA 926, aka Business US 169 in Fort Dodge; IA 934, University Avenue in Cedar Falls-Waterloo), and two secret routes created (IA 461, Business US 61 through Davenport; IA 906, that part of US 6 on Kanesville Boulevard east of Broadway that wasn’t turned over to Council Bluffs).
And then we got the out-of-nowhere shock to the system: The eastern half of I-680, between I-29 and I-80, was renumbered I-880. Some people may point to this as a case of state governments adapting to global warming, because this was precipitated by an unusual “bomb cyclone” that left vast areas of the Missouri River floodplain under water at a time of year it should not have been.
I, however, just want to hate it because I believe it is both unnecessary and the wrong type of number to assign. I-880 by itself doesn’t form a loop or partial loop, and/so it should have been numbered I-329, I-180, or I-580 (to avoid confusion with the nearby-ish I-180 in Lincoln). An odd-first-digit route can still have both ends at another interstate; see I-155 in Illinois and I-196 in Michigan.
October 11, 2015: 
