Thirty years ago today, U.S. Route 66 was officially removed from the United States Highway System, 59 years and 58 days after being named. This highway, which even today is still one of the most famous roads in America, originally stretched for 2,448 miles (3,940 km) from Chicago, Illinois through Missouri, Kansas, Oklahoma, Texas, New Mexico, and Arizona before ending at Santa Monica, California. It was one of the major routes of westward migration and business along the route tended to prosper and do well before it was bypassed by the Interstate Highway System. And it is still so iconic that portions of the route have been designated a National Scenic Byway and some states are adopting bypassed sections into the state road network as State Route 66.
For decades this was a main route for the movement of military equipment in the USA and, especially before the introduction of the interstate highway system, was a major route for trucking companies shipping goods from the coast to the mid-west (as one could get from Los Angeles to Chicago going down only one road). The route was so central to US logistics that there is even a TMS (Transportation Management Services) company that goes by the name Route 66 Logistics.
The history of this route, before, during, and after service and of the historic associations trying to preserve it over the last 30 years is fascinating (and goes well beyond what the younger generation, whose entire knowledge of the route might be from Cars, will remember). If you have the time, check out the linked Wikipedia article and related resources.