The Lincoln Highway was the first transcontinental highway in The United States. In 1919 a young army officer by the name of Dwight D. Eisenhower joined with a group of fellow army soldiers who were going to attempt to cross the country, in a convoy of 80 trucks, motorcycles, and other vehicles, using the route of The Lincoln Highway. It was quite the slog with bridges that didn't hold the weight of the vehicles, or their size, and roads that were more mud than dirt. At that time in the early 20th Century, The Lincoln Highway was a series of roads stitched together by The Lincoln Highway Association and their map into a single route to follow from Times Square in New York to Lincoln Park in San Francisco. Here is a great link to more on that famous trip.
The Interstate Highway Law.
Eisenhower's experiences on that trip left a mark, when as President, on June 29th, 1956 he signed into law The Interstate Highway System. The bill created a 41,000-mile "National System of Interstate and Defense Highways" that would, according to Eisenhower, eliminate unsafe roads, inefficient routes, traffic jams and all of the other things that got in the way of "speedy, safe transcontinental travel."