Ford reveals self-driving cars; politeness may be a problem

Of all the possibilities that might give pause concerning self-driving cars, here's one you might not have considered: politeness. Monday, experimental white Ford Fusion sedans, their roofs bristling with sensors, drove themselves down curvy streets, obeyed stop signs and traffic lights, braked at the right times and made left-hand turns while a Ford driver sat at the wheel, never touching the controls. At one point, a polite human being, waiting by the curb in the crosswalk, tried to wave the car through with a "no, you go first," look on his face. The car, programmed to stop for people in a crosswalk, didn't know what to do. So it just sat there. From a safety perspective, that was proper.