In the alternate timeline I write in, I’m deliberately vague about highway, route, and road numbers, largely because it starts to diverge from real life around 1900, and diverges in earnest around World War I in 1914…which is before even the United States Numbered Highway System (better known as the US Route system) was created, let alone the Interstate Highway System. In real life the highway numbers and their routings were first laid down comprehensively in 1926, though with substantial modifications thereafter.
So with 26 year of divergence, butterfly effects, et cetera, there’s no particular reason to assume that the numbering system would be the same; indeed, it’s as likely as not that it would be substantially different from real life! In what ways? Well…it’s pretty much a blank canvas if you’re a worldbuilder like me, but that’s also an intimidating prospect, hence why in my stories I’ve tended to have characters refer to freeways by name. The Nashville crowd, for example, talk about the “Long Hunter Freeway”, rather than Interstate 40 or US Route 70 (or any other number).
That’s a choice and a change from real life in itself, but it has precedent; in Alaska route numbers are rarely used, with names being preferred instead, and historically this was the case in southern California as well (hence the dialectical e.g. “the 10” (referring to a segment of Interstate 10), which ultimately stems from “the 10 Freeway”, which in turn evolved from “the Santa Monica Freeway”).
Nevertheless, like California in the old days or Alaska today, these roads would all have numbers (probably…). How would the system evolve? The US route shield, when the powers that be get around to creating a national numbered highway system, might be substantially the same; it was deliberately modeled on the shield found on the seal of the United States, a design that was set as far back as the 18th century, and the most obvious source of inspiration.
One change I envision is the Interstate Highway System never being created; freeways are built out across the country as early as the 1930s, much sooner than in real life, but like many of the earliest freeways in real life these carry the US Routes as appropriate, rather than being part of an entirely separately signed system. This would in real life be analogous to if in Arizona and New Mexico the current routing of Interstate 40 was signed as Route 66, rather than the former having replaced the latter altogether.
So the routings might be significantly different locally, and even regionally; for example, US Route 1, as the easternmost of all primary highways, might just have easily been routed through the Outer Banks and into Charleston and Savannah rather than having been drawn substantially inland. And so on and so forth.
For that matter, would US 1 even be a primary highway? Or even be located in the easternmost part of the United States?
As things stand now, and were designed in 1926, the US Routes are numbered in a grid system: lower numbers in the north and east, higher numbers in the south and west, with north-south routes having odd numbers and east-west routes having even numbers. Numbers ending in “1” were primary north-south routes; 1, 11, 21, 31, 41, 51, 61, 71, 81, 91, and 101 (the latter having a first “digit” of “10”). Numbers ending in “0” were primary east-west routes (90, 80, 70, 60, 50, 40, 30, 20, 10…and 2, because reasons?).
In my view some details of this system are a bit weird (“10” as a digit, “1” as the ending of primary route numbers, and “2” being a primary route despite not being a multiple of 10), with the Interstate Highway system making much more sense (all east-west primary routes are multiples of 10, and primary north-south routes end in 5 rather than 1). Considering the Interstate Highway System was created in the 1950s, only a few decades later, it might be possible that some characteristics of its numbering scheme would appear earlier in the US Route system. To wit, US Route 1 would be numbered as Route 5, with US Route 101 being numbered as Route 95. Yes, there’s one less “primary” routing in this system, but so what? Perhaps the politics between these states and localities shake out a bit differently.
Primary routes ending in “5” would also make at least the West Coast routings much more sensible, because there’s room for two north-south routes west of what’s now US 101. What’s now US 101 could be US 95, with US 97 and 99 being freed up for a direct coastal road, which in California is now signed as California State Route 1. US 99 in the grid would be westernmost primary route, which makes perfect sense for a Pacific Coast road; there are no road routings possible that are west of there!
But I’ve found this solution a bit unsatisfying; California State Route 1 is just so iconic, with its simple low number that just oozes “I’m the most important road ever”, and frankly sporting the natural and human beauty to back up that claim.
Then I got the idea: why not flip the grid so that instead of low numbers being in the east, they’re in the west? After all, this was done for the Interstate Highway system (on purpose; US Routes have the lowest numbers in the north and east, and Interstates have their lowest numbers in the south and west, to minimize overlapping numbers in the same areas of the country), so why couldn’t it have been done for the US Route system a few decades earlier?
Indeed, this lends the alternate US route system a much more alternate-historical feel; in particular, if you keep the east-west grid the same, you end up with a situation where the lowest numbers are found in the north and west, and the lowest numbers in the south and east, which is unlike any national numbering grid we’ve had in real life! Ooh…
The real clincher is how the Pacific Coast Highway could still be Highway 1, but with a US Route shield instead of a California State Route shield. Satisfying, especially with how the West Coast is far more important a region to the US in my timeline than it even is in real life, along with the American West in general; how appropriate that it gets the lowest and studliest numbers!
A bonus is that as a nationally numbered road, Highway 1 would extend beyond California, on roughly the routing US 101 is on now, through Oregon and Washington…and perhaps beyond.
An extension of the US Route system into Alaska has been contemplated on several occasions; a mid-20th-century proposal that was kicked around was to extend US 97 through the Alaska Highway to Fairbanks, but British Columbia’s failure to coordinate led to the plan being shelved. Slightly odd, since US 2 was posted in two segments that connected through Ontario despite Ontario never having put up any “Highway 2” signs anywhere, so one would think US 97 could have just been signed in Alaska, but whatever.
The original US Route system didn’t include Alaska, but the state does connect to the rest of the continent overland. As of 1926 no road connections existed, but the eventual buildout of such might have been anticipated and planned for even that early.
In that case US 1 would be reserved for a Pacific Coast road, which in Alaska’s case would follow the northwest-southeast-oriented coast around the Inside Passage and then arc around into a more west-east orientation, before following a northeast-southwest orientation around the Aleutian Islands. It bends the grid, but it doesn’t necessarily break it.
If, like the Interstate Highway System, the northernmost route in the contiguous US has a number ending in 0, then this alternate timeline’s version of US 2 would be designated US 10; this frees up US Routes 8, 6, 4, and 2 to be used in Alaska later. In my story “Last Light” there’s a freeway connecting Barrow and Prudhoe Bay by the mid 21st century; since that’s the northernmost stretch of land in the United States and it follows an east-west orientation it would be eminently sensible to designate that highway as US Route 2.
There is a route stretching westward from Fairbanks to Nome across the Bering Strait into Siberia, so that may well carry another one of these spare east-west routes, perhaps US Route 4, though that might be reserved for a route traversing the Brooks Range crest at the Continental Divide, in which case US 6 might be its designation. This leaves US 8 available for a route traversing the Alaska Range. Alternatively, US 5 could be the Alaska Highway from Canada into Fairbanks and then be extended east-west all the way to Siberia, though it might be more consistent with the grid for it to jog northward and follow the route between Fairbanks and the North Slope. In that case US 3 would make a fine designation for a road traversing the Bering Sea coast; think Nome to Bethel, places like that.
I know that’s probably putting more thought into it than the planners themselves likely would, but whatever; this is fun stuff! I might work out the exact details of these routings later.
For the southernmost routing, it would likely in this timeline take the number US 90, which potentially frees up US 92, 94, 96, and 98 for use in Hawaii (or Puerto Rico, but in this timeline they become independent rather than a state, so they wouldn’t be relevant to the system down the road). But unlike Alaska Hawaii has no even theoretical road connections with the rest of the country, so there’s a chance they could be left out altogether in even a more expansive original vision for the US Numbered Highway System.
Florida and South Texas “jut” out from a more or less straight east-west-routing across the southern tier, so US 92, 94, 96, and 98 might be deemed more useful for them anyway. We see similar logic where Interstate 2, the southernmost possible designation in the grid, is currently used for the lower Rio Grande Valley in Texas, right next to the Mexican border and near the southernmost latitude reached by the contiguous United States.
Lots of possibilities, some of which might be explored in a more expansive and ambitious vision for the US Route system. In particular, aside from the grid change and the extension of the system into Alaska, the biggest change I’m thinking from real life is leaving more room for primary route designations in the western United States; instead of packing more route numbers into areas that have more population, spread them out more evenly by land area, so that when the American West becomes more heavily populated and connected by road and highway later on primary (i.e. two-digit) numbers can be dusted off the shelf. How exactly this will play out with which routings get which numberings is a big project and a lot of labor, which I don’t have the time to go into now, but staring at this map of the original 1926 numbering plan…I think it’s a labor of love that I will do someday. It just makes the world I have in my head seem all the more real and compelling. I like this stuff… 😇
