Since 1956, the Interstate Highway System has been standardized down to the uniform thickness of pavement — with one exception. Some public rest stops look like teepees, others have picnic tables and BBQ pits. All offer relief from the road for free. But they're a vanishing species, they're losing out to commercial alternatives, as drivers and passengers may discover during this busy travel season. That's according to Ryann Ford, a photographer who's worked for the New York Times, Texas Monthly and other publications. She spent four years shooting pictures for her project, "The Last Stop: Vanishing Relics of the American Roadside."