That changed in 1925, when state transportation officials convened a Joint Board on Interstate Highways. After a year of taking comments on its original proposal, the board unveiled the new highway numbering system on Nov. 11, 1926.
The U.S. Highways (often called U.S. Routes) were the fastest way to drive from one place to another for three decades, until the Interstate Highway System was created in the 1950s, building even speedier purpose-built multi-lane roads.
Some U.S. highways retain something of an iconic status, and they’re ideal for travelers seeking a true road trip with lower speeds, better scenery, out-of-the-way towns and lots of history. Route 66, for example, still retains its old charm. The Lincoln Highway, the first transcontinental road, still cuts through the middle of the country from New York City to San Francisco (the section through the Nevada is sometimes called “the Loneliest road in America” and is great for escaping the rest of humanity).
For U.S. Routes, north-to-south highways are usually odd-numbered, with numbers going from low to high as you travel from east to west. West-to-east highways are typically even-numbered, and numbers go from low to high as you move north to south.