There are five widely accepted levels of driverless vehicles which are:
Level One – Assists the driver with some parts of driving such as braking pressure during an emergency stop.
Level Two – Can take over some parts of driving. Automatic emergency braking and lane-keep assist both fit this description.
Level Three – Can drive itself, but only in certain environments, such as on motorways, and for very limited periods. The driver must take back control when requested and so must be ready to do that.
Level Four – Drives itself for sustained periods without needing input from the driver. However, it can only do this in certain areas.
Level Five – Lastly, there’s complete A-to-B self-drive with no input from the driver.
Connectivity – Vehicles can be self-driving or connected, or self-driving and connected. Connected vehicles use a number of communication tools to relay information to the driver, to other vehicles (known as vehicle-to-vehicles communication), to roadside infrastructure known as vehicle-to-infrastructure communication), and to the cloud.
This information could include anything from size, shape, construction material, speed limit zone, traffic, informing a vehicle of is surroundings to aid in steering, speed, and decision making.
In theory, connected vehicles allow drivers and self-driving vehicles to have a 360-degree view of the road landscape.