Origin of US 412's number

[usends]

In 1980 Arkansas, Missouri, and Tennessee jointly requested the specific designation US 412 for a route across the three states.  After initially balking at the number "412" at their June 1980 meeting, AASHTO approved the proposal later that same year (at their Nov. meeting).  So the questions are:

• How did those states arrive at the number "412"?
• Why did AASHTO approve it, after initially rejecting it?

That was discussed a bit in this thread, where in post #168 Mike asked the question, "Was that the lowest number that didn't conflict with state route numbers in any of those three states?"  (After all, it's generally desirable if state DOTs don't have to renumber existing routes when a conflicting US route number is approved for their state.)  So I recently spent a little time investigating that possibility, and here is what I've found so far:

• In 1980, TN seems to have been still working through their 1xx numbers.


• It appears most 2xx and 3xx weren't used until 1983 or later.
• 400 wasn't used until 1986; 416 was 1987-88 (and there have been no 4xx state route numbers in between those).
• So in 1980 TN wouldn't have had any reason to leapfrog straight to the 4xx range.
• MO didn't have any 4xx numbers at the time (and even now has only a couple).
• In 1980 AR was getting close to using up all of its 3xx numbers.
• 392 and below were commissioned in the 1960s.
• 393 and above were commissioned in the 1970s.
• Not many 4xx numbers are in use even now, and the few that exist appear to have been designated in the 1980s.
• So it seems pretty clear that AR was the only state that would have had a reason to propose a 4xx number.
• But the reason for the specific number "412" is still unclear.

However, it's only a matter of time before someone uncovers a historic document that explains the rationale.  My hope is that this thread will be used for posting that discovery.
Meanwhile, this post provides some necessary background for understanding the likely reason for US 425's number, which is discussed in this thread.

[CNGL-Leudimin]

Now it is clear Arkansas paved the way for me to make an elaborate April Fools prank in 2019, with an even more elaborate follow-up two years later. Now I think, I should start working in the one for this year.

[Scott5114]

Even if the reason to pick a 4xx number was to avoid conflicting with state routes, 470 was available–why was that not considered?

Edit: Okay, I remembered I-470 exists in Missouri, but it's catty-corner to the bootheel where US-412 is found, and Missouri doesn't seem to have a problem with duplicated routes (US 59/MO 59, for instance, and the more recent duplication of MO 110). Did Arkansas and Tennessee just assume Missouri would have a problem with duplicating the number 470 and just not even bring it up as a possibility? If so, why not 570?

Did any other east-west routes besides 70 intersect US-412 at the time of its creation?

[usends]

Even if the reason to pick a 4xx number was to avoid conflicting with state routes, 470 was available–why was that not considered?

Edit: Okay, I remembered I-470 exists in Missouri, but it's catty-corner to the bootheel where US-412 is found, and Missouri doesn't seem to have a problem with duplicated routes (US 59/MO 59, for instance, and the more recent duplication of MO 110). Did Arkansas and Tennessee just assume Missouri would have a problem with duplicating the number 470 and just not even bring it up as a possibility? If so, why not 570?

Did any other east-west routes besides 70 intersect US-412 at the time of its creation?

Correct, I believe US 70 was the only one.  However, the question assumes that Arkansas both a.) understood US highway numbering conventions and b.) cared about them.  But given that they proposed US 412, 425, and 427 over the course of a 14-year period, I have to conclude one or both of those assumptions were actually not true.  Even if they hadn't known, they were surely made aware when AASHTO questioned the 412 number in 1980.  So to me it seems more likely that in AHTD's thinking, their own route numbering issues trumped any concerns related to the national numbering system.  (As supporting evidence for that statement, I note that the AASHTO archive has documentation from a few years later showing that AHTD petitioned AASHTO to decommission parts of US 62 and 63 in their state, because they didn't want to triple-sign those routes with 412.)

[Scott5114]

Sure, but AASHTO has the power to say "approved, but we're changing the number to this", as they ended up doing with 427→371 (and as they've done more recently with North Carolina's interstate requests). So why was this not considered worth doing with 412? Was 427 simply the "last straw" and they started enforcing the numbering rules more seriously thereafter?

[hbelkins]

Tennessee has no qualms about duplicating US and state route numbers. Most of the duplicates have some geographical separation to them (TN 25 and US 25, TN 31 and US 31) but US 70 and TN 70 come fairly close to each other.

So the existence of a state route number in Tennessee wouldn't have been an issue.

US 412 would work well as a child of a number of even two-digit US routes.

[Mapmikey]

A few notes:

Tennessee did/does have a TN 412 as a secret interstate designation (though I don't yet know for which one).

Tennessee also duplicates state/US route numbers

The Arkansas Highway Commission minutes suggest that the Chambers of Commerce came up with both the idea for a US route corridor and the number 412 itself.
Page 6 - http://www.ahtd.state.ar.us/minute_orders/MO80-89.pdf

[usends]

Sure, but AASHTO has the power to say "approved, but we're changing the number to this", as they ended up doing with 427→371 (and as they've done more recently with North Carolina's interstate requests). So why was this not considered worth doing with 412? Was 427 simply the "last straw" and they started enforcing the numbering rules more seriously thereafter?

That's a great question, complicated by the fact that, although AASHTO rejected the number 427 in June 1994, in Nov. 1994 they approved the US 400 designation.

[Scott5114]

A few notes:

Tennessee did/does have a TN 412 as a secret interstate designation (though I don't yet know for which one).

Tennessee also duplicates state/US route numbers

The Arkansas Highway Commission minutes suggest that the Chambers of Commerce came up with both the idea for a US route corridor and the number 412 itself.
Page 6 - http://www.ahtd.state.ar.us/minute_orders/MO80-89.pdf

This adds yet another wrinkle to this, since this would lose the corridor a lot of points in the scoring system that AASHTO used in the 80s to evaluate applications (one reason the US-377 extension in OK was rejected so many times was because it was being promoted by a local booster organization, which put it under the point threshold needed for approval).

[usends]

Tennessee did/does have a TN 412 as a secret interstate designation (though I don't yet know for which one).

If TN 412 is/was their secret designation for I-155, then the mystery could be solved...

[Mapmikey]

Tennessee did/does have a TN 412 as a secret interstate designation (though I don't yet know for which one).

If TN 412 is/was their secret designation for I-155, then the mystery could be solved...

Here are the ones I know:

I-24 - TN 401
I-40 - TN 402
I-55 - TN 403
I-65 - TN 404
I-75 -
I-81 -
I-124 -
I-155 - TN 408
I-240
I-255
I-265
I-275
I-440


So clearly the gaps up through 408 are obvious and it is likely the trend continues through the I-265 designation.  Then after that I don't know because it depends on when they assigned these versus when other interstates came to be.  Plus, what happened when I-255 and I-265 were absorbed into existing interstates?  Plus now there are more Tennessee interstates than 401-415 can cover.  Does this mean some of the missing 4xx routes higher up the number line were given to say I-269?

Despite all that, Tennessee wouldn't object to US 412/TN 412 on the same road since they already have US 27/TN 27 doing this.

[usends]

The Arkansas Highway Commission minutes suggest that the Chambers of Commerce came up with both the idea for a US route corridor and the number 412 itself.
Page 6 - http://www.ahtd.state.ar.us/minute_orders/MO80-89.pdf

Update: the document referenced above is now located at this URL:
https://www.ardot.gov/wp-content/uploads/2020/10/MO80-89.pdf