The cars which we have today, maximum of them are manual. And we are expecting autonomous or semi-autonomous vehicles till 2025. And the transition from manual to autonomous has 6 levels. Society of autonomous Engineering defines 6 levels of self-driving cars based on their ability to drive on the road.
Level 0: No Automation
The maximum of the cars on the road at present are level 0 cars. They provide issue warnings to the drivers only.
Level 1:Driver Assistance
These types of cars either control steering or speed but not both at the same time. Adaptive Cruise Control keeps the speed of the car under control. This keeps a safe distance between one car and the other car ahead of it by using radars and/or cameras to automatically apply to brake when traffic slows.
Lane centering assistance provides continual steering to keep the vehicle center in its lane.
This system will assist the drivers but the driver has to keep his hands on the steering all the time.
Level 2:Partial Automation
At this level, the automation system controls both steering and speed at the same time. But at this level, the drivers should have hands on the steering wheel, mind on.
There are several cars that are equipped with a level 2 automation system. Some of them are Tesla Model S, Toyota RAV4, Volvo XC60.
Level 3: Conditional Automation
This is starting of the level at which tasks for human reduces. This is an automated driving system(ADS) which drives in some specific condition and they have several limitations. When these conditions not met they will not be able to drive. Driver does not require to control the steering all the time. But they need to keep their mind on. And when the system starts to fail, he needs to take control over it.
Level 4: High Automation
At this level the car drive everywhere. But they also have limitations. They sometimes get confused about what to do. But they can stop when they feel the inability to drive.
Level 5: Full Automation
These types of cars are dreams and targets to be achieved. They can drive whenever and wherever be the situation. Here all humans are passengers.