As you may or may not know, Matthew Salek, the Colorado highways guru, originally maintained this page. In January 1999, he wanted to get rid of that page so he could focus on the other parts of his website. So, I took it over. This site retains almost all of the information from his page.
Pretty much every highway criss-crossing the United States and Canada has a number. While you might never have given much thought to it, did you ever wonder how the highways get the numbers they do? Most jurisdictions that create highways have some sort of system to assign the numbers.
On this page you will find:
Introduction
The American Association of State Highway and Transportation Officials has set the guidelines for numbering Interstate and US highways. Whenever you hear about a US highway that gets "commissioned", that means that AASHTO has officially commissioned a US highway along a particuar route. It should be noted that the US highway system is not any sort of specially funded road system. US highways are simply routes that states get together (through AASHTO) and decide should exist. They exist simply to guide drivers. Heck, the entire US system could be scrapped, and nothing would change except the signs.
You will see the term "geographic" a lot on this
page. When a jurisdiction numbers highways with the geographic system, this
means that the numbers increase sequentially across the jurisdiction. These
systems also usually have a rule where north-south routes are even and east-west
routes are odd, or vice versa.
Calls for Information
If you have information on how a state or province numbers its highways, don't hesitate to e-mail me.
Last updated February 12, 2000 (added 896, some more high-low, updated VA, MA, PA, UT)