A closer look

Before GPS, cell phone tracking, and dystopian traffic cameras, managing the nightmarish sprawl of American car culture relied on literal rubber hoses. These pneumatic road tubes were laid across intersections; every time a heavy car tire crushed the tube, a burst of air triggered a mechanical clicker in a metal box chained to a pole. It was an ingeniously simple solution, mostly because 1960s city planners had no better ideas.