Benedict Evans:

The standard way to talk about autonomous cars, shown in this diagram, is to talk about levels. L1 is the cruise control in your father’s car. L2 adds some sensors, so it will try to slow down if the car in front does, and stay within the lane markings, but you still need to have your hands on or near the wheel. L3 will drive for you but you need to be ready to take over, Level 4 will drive for you in some situations but not others, and Level 5 doesn’t need a human driver ‘ever’ and doesn’t have a steering wheel.