COLUMBUS, Ohio — Used to be, Dad would stuff a half-dozen maps in the glove box before setting out with the family on a road trip to see the waterfalls at Yosemite or the granite faces of Mount Rushmore. Colorful maps bearing the logos of the oil companies that printed them – names like Texaco, Gulf, Esso – once brimmed from displays at filling stations, free for the taking. But with millions of Americans expected to travel by car this summer, a good chunk will probably reach for technology before they’re tempted to unfold – and in a tradition that used to bind Americans as tightly as a highway cloverleaf, try to refold – a paper road map.