With the Federal Road Act of 1916, the U.S. government made funds available to states for new highways. This Act promoted the interaction between the states and the federal government in choosing, building, and fixing roads and highways. Largely attributed to Henry Ford and the democratization of the automobile, road construction gained momentum in the 1920's. Subsequently, in 1921 the Federal Highway Act, a modified version of the Federal Road Act, called for the construction of interconnected interstate highways. More significantly, this new Act ensured that unless states devoted seven percent of their roads as national highways, they would not receive any federal revenue. This new energy towards road building, however, was just the beginning of America's innovative highway system. By 1920, out of the three million miles of road across the continent, only 36,000 miles were auto-friendly.
In 1921, in addition to the new Federal Highway Act, Cyrus Avery, an Oklahoman interested in local roadways, was elected president of the Associated Highways Association of America. Avery, a driving force (if you will) behind America's new means of transportation, was also appointed as state highway commissioner of Oklahoma in 1923. In 1924, another organization, the American Association of State Highway Officials, met in San Francisco. Avery, of course, was a significant player in this organization. As a result of the San Francisco meeting, the Secretary of Agriculture appointed a twenty-one member board to deliberate with the 48 state highway departments. Appointed by the Secretary as a "consulting highway specialist," Avery assumed the arduous task of creating the U.S. Highway System. This System would select certain roads for improvement and construct a map showing America's new drivers the most important interstate highways. The foundations of U.S. Highway 66 were taking shape.
In 1925, Avery and others began selecting roads for the national network of highways. Their mission: make traveling easier. In response to their national interest, more than 250 road clubs lobbied for their designated trails to be included. They eventually decided on a transcontinental road between the Northern Santa Fe Trail and Southern Butterfield Stage Line.
Remembering the three million miles of highway already sprawled across the continent, the national highway commissioners assigned numbers to the existing roads. Even numbers represented East to West highways, odd numbers signified the North to South routes. Shield shaped signs indicated interstate highways while circular signs signified state roads. Main highways were numbered under 100 and more prominent roads ended in zero (40, 50, 60, etc.).
The road starting in Chicago and ending in Santa Monica was initially supposed to be Route 60. Protests from Virginia and Kentucky road constructors, however, led Avery and his crew to think of new names. Thus, after months of debate and with the impending fear of congressional intervention, they decided on the catchy, easy-to-remember number, "66."
On November 11, 1926 a committee of federal and state highway officials met in Pinehearst, NC to sign off routes in all 48 states. And, by 1926, 800 miles of the 2400 were already paved. Yet, not until 1937 would the entire 2400 mile road be paved. Soon after this momentous occasion in 1926, Cyrus Avery and the Missourian John Woodruff organized the National U.S. 66 Highway Association.