I was curious why in the 1950s the new US 431 was allowed to wipe out the long-established US 241, when instead US 241 could have just been extended north, and there would have been no need for the US 431 designation. Recently I came across several documents in the AASHTO archive that shed some light on that situation. Among other things, I learned:
- US 241's circuitous route through Alabama was a result of local towns vehemently protesting ALDOT's attempt to reroute traffic through a more direct corridor.
- The north end of US 241 wasn't always in Murfreesboro TN. It was truncated to Huntsville AL for about a year before it was completely decommissioned.
- The south end of US 431 wasn't always in Dothan AL. For about four months it went only as far as Fayetteville TN (before it essentially replaced 241).
- After the dust had settled, US 241 was gone, and in its place stood three new x31 routes.
Full article here (https://www.usends.com/blog/the-intertwined-history-of-us-routes-241-231-331-and-431)
As far as Kentucky is concerned, 241 would have made more sense. The US 431 corridor is much closer to US 41 than to US 31.