Updated: May 4, 2021
If you’ve been traveling around the United States, or just driving around locally, you have undoubtedly seen the iconic black-and-white shield symbol signage with the route number placed squarely in the center. It might look something like this:
There is a story behind that shield symbol -- a story that traces the humble beginnings of the first American highway system from the introduction of the automobile to the first transcontinental highway in the United States (the Lincoln Highway) to the establishment of the American Association of State Highway & Transportation Officials (AASHTO) in 1914.
Early Years of U.S. Automobile Travel
Prior to 1913, the United States was loosely stitched together by a hodge-podge of unimproved roads that were poorly maintained and not well marked. Wet weather conditions would often make these roads entirely impassable while hot, dry weather would make them dusty and rough. In 1912, only 7% of these roads were graveled macadam or even graded. There were only a few hundred miles of brick paving. The vast majority of U.S. roads in those days were just rutted dirt.
To make matters worse, there was no road network per se. In those days, roads were designed to move goods from farms to transportation hubs, i.e., rail centers. Most roads radiated out from larger towns connecting the outlying farming communities, but they did not necessarily connect with neighboring cities. A series of auto trail associations sprang into existence around this time all over the country -- each dedicated to the task of identifying, naming and raising funds for improving their local roads.
The Lincoln Highway was the first official transcontinental passage from New York to California in 1913. This will be a topic for a future blog post -- stay tuned!
Though AASHTO was founded in 1914 for the purpose of setting roadway standards, it did not seriously get down to the task of planning a system of marked and numbered "interstate highways" until 1924. In 1925, they settled on the shield symbol as the roadside marker for the highway number. The idea of the shield was inspired by the Great Seal of the United States. Later that year, they also decided on an orderly system of numbering that would be applied to major interstate and state highways. The final plan for the U.S. Highway system was released in late November 1926:
The U.S. Highway System Takes Shape
After 1926, existing roads on newly designated routes were improved and marked, while new roads were beginning to be built to create the interconnected U.S. Highway system. Perhaps one of the most iconic of these new routes was U.S. Route 66, connecting Chicago with Los Angeles. These new highways made cross-country travel much easier and were the primary means of movement by car from state to state, region to region, coast to coast. It was alongside these highways where the first convenient overnight lodging -- the motor-hotel, or "motel" -- made its debut. The first roadside diners popped up along these nascent roadways to feed the hungry traveler, and the first drive-in theaters soon followed. The U.S. Highway system's heyday lasted for a little more than 30 years, stretching from 1925-26 to the late 1950s when the Eisenhower Interstate System was introduced, and once again, the way we travel changed.
But What Do The Numbers Mean?
The highway numbers appear to be randomly assigned -- looking at them you probably could not suss out an obvious reason for why they were selected. However, if you were to look at a map of the United States, a pattern does emerge. First of all, all major highways have single- or double-digit designations. They scale from “1” to “99”. Highways that run east-west all have route numbers that end in an even number. All of the original transcontinental highways, i.e., those that run east-west from one coast to the other, end in "0" (zero). They graduate from "10" in the northern tier of the country by multiples of ten as you move toward the south where the last one is numbered “90”. US 20, for example, stretches from Boston, Massachusetts to Newport, Oregon. US 50, in the middle of the transcontinental pack, runs neatly across the center of the country, right through the heartland, from Ocean City, Maryland to Sacramento, California. (The part of US 50 that passes through Nevada is known as "the Loneliest Road in America.") There was one exception to the "end in zero" rule -- US 2. It is the northernmost transcontinental byway in the country, starting in Houlton, Maine and terminating in Everett, Washington. Since US 10 had already been designated, this northernmost route was numbered "2" in order to avoid having a US 0.
North-south routes all end in an odd number. Major north-south routes that largely connect the country's northern frontier with its southern frontier end in "1". US 1 is the best example of this kind of highway, linking Ft. Kent, Maine with Key West, Florida. The numbers increase as you move from east to west. On the West Coast, there is one anomaly -- Highway 101. For the most part, three-digit highway numbers were used to designate U.S. highway spurs, which are usually shorter highways that are more or less offshoots or secondary routes of a major highway. The problem with this plan was that the last two-digit odd number that could be assigned for major north-south highways was "91" and that would mean 93, 95, 97 and 99 could not be used (those highways would have to be situated "west" of the last major highway on the Pacific coast). An exception was made in this case, and "101" was assigned to the westernmost highway traveling in a north-south direction. Today, US 101 connects Olympia, Washington with Los Angeles and mostly hugs the coastline of the Pacific. Interestingly, US 99, not considered a major north-south route, prior to the arrival of Interstate 5, was the primary motor route for people traveling from Seattle to Portland to Sacramento to Los Angeles and finally to Mexico. It stretched from the Canadian border to Calexico, California until it was decommissioned in 1964. Today, US 99 is California S.R. 99, Oregon S.R. 99 and Washington S.R. 99.
The highway shield design has undergone a few changes over the years. Until 1961, the shield also bore the name of the state the highway was passing through. On a drive through Needles, California in 1998, I had a rare sighting of a reproduction of the original U.S. Route 66 sign bearing the CALIFORNIA designation.
The original American highway system remains as the most scenic and interesting road network for me today. These are the highways that pass directly through towns instead of going around them to save time. They tend to be narrower and more likely to follow the contours of landscapes. Because they have a somewhat slower pace and winding nature, there are more scenic turnouts and views along them for the enjoyment of the casual motorist. They also pass by some of the oldest and most established attractions, including National Parks, monuments and recreational centers. If you’re traveling to see things along the way, these are the best highways to take. Although large portions of the U.S. Highway system were supplanted by the Interstate System starting in the early 1960s, most of it survives today and is just waiting to be explored.
Just because it's one of my favorite places in the county, here's US 163 passing through Monument Valley on the Utah-Arizona state line:
. . . Until next time, dear travelers, may all your journeys be safe and rich in experience!