In the decade since I created the Sioux City Highway Chronology page, the amount of resources available for related research has grown substantially. Those resources include PDFs of year-by-year maps previously available only for study in Ames, construction plans/documents, and extensive documentation of the Grand Avenue Viaduct.
With those resources, I went through the maps and timeline, making small changes in some places and larger ones in others. I took out the 1956 map in favor of 1952 (after US 77 was moved to along the river, but before I-29 was born) and then created a 1962 map that shows the relatively short-lived IA 7 (1957-68).
There are some cryptic notes in the 1950s, based entirely on presence or absence of shield icons on city insets. The 1952 map was the first in 20 years to have insets at all.