This level has you totally in charge. The car does no ‘thinking’ for you. That description covers most cars for sale today.
This is the lowest echelon of autonomy, and refers to vehicles with a single type of driver assistance, be it electronic control of the steering, braking, speed modulation, etcetera. A vehicle fits into Level One as long as it is equipped with even a single example of the technology above.
This covers vehicles that can automatically steer and adjust speed. However, the driver can override these technologies and remains in control at all times. A car would be considered a Level Two vehicle if it was equipped with “one or more driver assistance systems” like a self-parking feature as well as lane-holding assistance.
Automakers currently sell vehicles that fit into the Level Two category.
Vehicles in this category have the ability to drive autonomously, and can make decisions independently of the driver, such as overtaking slow-moving cars on the freeway. However, Level Three vehicles still need the human touch for when they are unable to make a decision and the automated system needs to be overridden.
While a manual override is still available, Level Four autonomous vehicles are able to make decisions if things go awry or if a system fails. In the majority of situations, the driver is not required, and the vehicle can be left to its own devices.
In Level Four, the vehicle will notify the driver when conditions are safe, allowing the driver to manually put the car into an autonomous mode.
The Level Five category imagines a vehicle that has much stronger environmental awareness than the other levels, and can transport cargo and/or people completely autonomously. A Level Five vehicle does not need conventional driving controls like a steering wheel pedals, and so a driver is not required.
Younger people who will grow up with autonomous motoring will not be afraid of Level Five, but I doubt whether sporting motorists today will be able to give up control to a bunch of diodes.