Iowa's "howdy neighbor" renumbering in 1969

[kurumi]

In 1969, Iowa renumbered several highways to provide route continuity (example: IA 60 to continue as MN 60). In a couple cases, pairs of routes were swapped (26/182, 322/254).

From Mark Roberts' Twitter (more info at his site):

[NE2]

Here are the complete renumberings (including a few that are missing from the map) from http://www.iowahighways.org/ :
33 -> 60 -> 5/17
*5 -> 7 -> 985
*17 -> 4 -> 39 -> 44 -> 15 (north)
13 (part) -> 76 -> 70 -> number was free
15 (south) <-> 23
26 <-> 182
81 <-> 114
142 -> 202 -> number was free
150 (part) -> 130 -> number was free
254 <-> 322
402 -> 21 (part)

[pianocello]

Huh. Something I never realized until now was that while a large majority of these changes were to match up with the neighboring states' routes, a few of these did the opposite. Well, sort of.

IA 64 in the western part of the state changed despite (maybe) connecting with NE 64, although I'm not sure if either were signed all the way to the Missouri River.
IA 150 was truncated in the eastern part of the state, but it was designated that way a couple decades prior with the intention to (allegedly) connect with US 150 in Illinois. However, I know US 150 never quite made it to the Mississippi, and I'm not sure if IA 150 was signed all the way to the bridge either.

[usends]

...I know US 150 never quite made it to the Mississippi, and I'm not sure if IA 150 was signed all the way to the bridge either.

People who have memories from that area have written to let me know that both US 150 and IA 150 were signed all the way to the river: https://www.usends.com/quad-cities.html

[Mapmikey]

...I know US 150 never quite made it to the Mississippi, and I'm not sure if IA 150 was signed all the way to the bridge either.

People who have memories from that area have written to let me know that both US 150 and IA 150 were signed all the way to the river: https://www.usends.com/quad-cities.html

Picture Proof it was signed at the bridge...

https://picclick.com/Rock-Island-IL-Postcard-CENTENNIAL-BRIDGE-Illinois-371895436165.html#&gid=1&pid=1

[pianocello]

...I know US 150 never quite made it to the Mississippi, and I'm not sure if IA 150 was signed all the way to the bridge either.

People who have memories from that area have written to let me know that both US 150 and IA 150 were signed all the way to the river: https://www.usends.com/quad-cities.html

Hey, look, I forgot to fact-check before posting. I stand corrected.

Makes it even weirder, though: at the same time that Iowa DOT is renumbering north-south routes to match up with other states, they decide to remove the numeric consistency at the Centennial Bridge, even when US 150 was still signed to the river.

[usends]

Makes it even weirder, though: at the same time that Iowa DOT is renumbering north-south routes to match up with other states, they decide to remove the numeric consistency at the Centennial Bridge, even when US 150 was still signed to the river.

Agreed: in light of the other changes, this one seems like it was counter-productive.  The only possible explanation I can think of is that Illinois might have already been planning to truncate US 150 (this would happen 3-4 years later, in 1972), and they might have shared that info with Iowa.  But even if so, I still don't see a benefit to Iowa getting rid of their 150 designation, and the 130 designation doesn't seem to have created any improvement.

[froggie]

Could just be that Iowa wasn't all that interested in 150.  If IDOT shared that they were intending a truncation of the US route, that'd give Iowa all the more reason to renumber.

The two weren't really all that well connected, or used, as a through route to begin with.

[iowahighways]

Could just be that Iowa wasn't all that interested in 150.  If IDOT shared that they were intending a truncation of the US route, that'd give Iowa all the more reason to renumber.

The two weren't really all that well connected, or used, as a through route to begin with.

Plus work was about to begin on I-380 in '69, and I-380 would eventually supersede IA 150 between Cedar Rapids and Urbana. When that stretch of I-380 opened in 1984, most of that old IA 150 segment was turned over to local control while 150 itself replaced IA 101 to end in Vinton. So the Iowa Highway Commission (they weren't the DOT yet) may have been thinking ahead when they decided to truncate 150.