What was the route number of the section of what is now US 160 in New Mexico through the 4 Corners? I see that the Colorado section was CO 40 and the Arizona portion was AZ 64...but what was the number for the short New Mexico section?
When you find out let me know. Actually, I believe the original designation for the Arizona segment was 364. I would therefore speculate NM originally used that for its little piece because it wasn't otherwise used. That road wasn't open till the mid 60s and became U.S. 164 not long thereafter.
New Mexico may not have even had a marker on it then, whatever number it was. Today when you drive through on US 160, you're in Arizona, then there's one single NM 597 sign for the turnoff to Four Corners, then a Welcome to Colorado sign. No welcome to NM signs, only way you realize you're briefly in NM is the 597 marker.
I wonder if it was even maintained by NMDOT and not the Navajo Rez when it was built. That wouldn't be without precedent in the region- US-191 from US 160 to the Utah Line is Indian 12 signed as TO US-191, and NMDOT didn't take over maintenance of 597 from the Navajo until 2000 or so.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.davidjcorcoran.com%2Fhighways%2Faz%2F160%2F191to191%2F3.jpg&hash=6dc4eafcf397efcbbdfe1374400c5d1885531735)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.davidjcorcoran.com%2Fhighways%2Faz%2F160%2F191to191%2F6.jpg&hash=3c2fb13dd49d7b32945e3f56c8e372805ff47511)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.davidjcorcoran.com%2Fhighways%2Faz%2F191%2F160tout%2F1.jpg&hash=07d803940a128b8d2daacc5f657ac677150e1a12)
Reassurance shield on US-191/BIA 12