• Caption: 1915 PPOO St. Joseph, MO

This guide was put out by the St. Joseph Automobile Club of St. Joseph, MO. St. Joe would soon become the headquarters of the PPOO Highway Association, but that was in Colorado Sorings in 1915. St. Joseph boasted no fewer than 12 auto auto trails either passing through or nearby, with the PPOO being the most major. Some of the others were the Sulpho-Saline Route, the Glidden Route, the Ayr Line Trail, the Saints Highway, and the Inter-State Trail.

This guide has a fold-out map of the PPOO attached to the back cover, showing an early routing following the National Old Trails Road from Washington, DC to Indianapolis and the Lincoln Highway west of Salt Lake City. In keeping with the "highway that couldn't make up it's mind" moniker, compare this route to the National Highways Association 1915 routing in the west (the PPOO is labeled #4), which has some local variations. A 1922 map shows both a route to San Francisco, with a more northerly Nevada section, and a separate routing to Los Angeles. It would be 1923, only 3 years before the federal highway numbering began, before the PPOO had it's own stable route on the eastern and western sides, with the Los Angeles terminus winning in the west.