In conclusion, the Highway Post Office offered the American people a reliable method of mail transportation. The HPOs were one step in the evolution of mobile sorting units. The first, and most successful, attempt used clerks on board specially-designed railroad cars to process mail while moving across the country. Other options, including Collection & Distribution wagons, trolley cars and airplanes, were tried over the years, with varying levels of success. Highway Post Office buses brought the efficiency of the Railway Mail Service to the highways as railways pulled back their service. While HPOs succeeded in their tasks, they were overtaken by the next step in mail processing progress – moving processing services back into stable buildings where a single piece of machinery could do the job of dozens of buses. The HPOs became irrelevant to moving the mail but not irrelevant to postal history. This White Motor Company bus, aka HPO #1, was a crucial part in this story. After thousands of miles and deterioration, the bus is fully restored and safely housed in storage. This piece of postal history has been preserved for the future.