Imagine you're road-tripping across the country 10 years from now. You spend a few minutes charging your electric vehicle and then set off — and your car's solar paint keeps it charged as you drive. Your eyes are on the stunning scenery, taking in the vistas along Route 66 or the grandeur of the Rocky Mountains, or you're catching up on messages. Your hands barely touch the wheel, and your foot doesn't push a pedal. Your car communicates with others on the road, so there's no need to brake suddenly or swerve. That's because it knows a vehicle five cars up from you has done so, and all those in between are slowing at exactly the right pace to avoid dramatic changes in trajectory.And when you ...