Eye contact is also a major component of driving a motorcycle safely.

When at an intersection, you know another car sees you by looking through their windshield and judging whether the person is distracted or if they're aware of your presence.

It would really benefit motorcyclists, pedestrians, and other drivers if there were some mechanism for self-driving cars to visually and outwardly acknowledge your presence.

How often do you wave or signal other drivers with your hands when you both arrive at a stop sign at the same time? What's the replacement for this in a world where half of cars don't have a driver?