Between the Great Depression and the mid-1970s, hitchhikers were a common sight for motorists, as American service members, students, and adventurers sought out the romance of the road in droves. Beats, hippies, feminists, and civil rights and antiwar activists saw "thumb tripping" as a vehicle for liberation, living out the counterculture's rejection of traditional values. Yet by the time Ronald Reagan, a former hitchhiker himself, was in the White...