Half a century after its heyday, the Alden StaRRcar clearly wasn’t made for its world. It looks like a white flatiron with wheels or a sleek, plastic bullet, dwarfed by the regal sedans of 1960s Detroit. It belongs in one of Buckminster Fuller’s domed cities, a vehicle for traveling under the geodesics of a bubble-topped Manhattan. Its future wasn’t one of highways, but of narrow cement tracks looping gracefully between city and suburb, connecting increasingly alienated parts of the American landscape. Once considered a key to solving urban blight, the StaRRcar was part of a public transit revolution that never was — but one that would help launch one of the weirdest and most politicized public infrastructure experiments of the 20th century. It’s an old idea that today, in an age of self-driving cars, seems by turns impractically retro and remarkably prescient.