ADAS is an acronym for Automated Driver Assistance System, and applies to electronic technologies that assist drivers in driving and parking functions.

Modern cars have sensors fitted that can monitor the surroundings and either alert the driver or take action in the event of a driver error.  Using electronic technology, such as cameras, radar and lidar, the area around a vehicle can be scanned for objects that the driver may or may have not have seen. Then, if a collision is imminent, the vehicle warns the driver in the form of an audio warning backed by a visual warning on the dashboard - or even a haptic vibration through the steering wheel or the seat.

If the driver does not react to the warnings the vehicle in some instances may automatically intervene, preventing a collision.

Not all cars have the full range of driver assistance functions. Many have individual technologies fitted as standard with others as optional extras. ABS is mandatory, and there are moves to make more advanced driver assistance technologies such as Auto Emergency Braking standard on a car.

Cars, lorries and vans can all have ADAS functions, even motorcycle, but they may vary from vehicle to vehicle type. In our guides to the specific technologies we note which types of vehicle have which types of ADAS.

ADAS or Advanced Driver Assistance systems are driver assistance systems aimed at supporting the driver who continues maintain full responsibility of the vehicle they are driving. Currently in the UK no systems are allowed on the public highways that allow a driver to drive hands free.

All current driver assistance technologies require the driver to always be alert and in charge.

Automated systems are future technologies where the driver can not only be “hands-off” but also “Eye- Off”  allowing them to do other tasks,  for example reading a book.

What are the 6 levels of Autonomy?

  • Level 0: no driving automation.
  • Level 1: driver assistance.
  • Level 2: partial driving automation.
  • Level 3: conditional driving automation
  • Level 4: high driving automation.
  • Level 5: full driving automation.

In the UK only Level 1 is allowed on UK roads, some countries allow Level 2 such as Tesla Autopilot which allows hands free driving.

Yes, modern manual cars can have ADAS too, although features like Adaptive Cruise Control require more driver involvement (for example matching speed to gears).


If Auto Emergency Brake activates what about the vehicle behind?


Auto Emergency Braking only activates if the vehicle senses it is about to hit an object in front.  It cannot brake the vehicle any harder than the driver can. The limiting factor being the brakes and the grip from the tyres. The brake lights are applied at the same time.

ADAS can be broken down in to separate functions but are often grouped together as they use the same sensors. A camera for lane departure warning can also be used for road sign recognition. A basic radar can equip a car with ACC and Forward Collision Warning.


Some vehicle manufacturers fit some of these systems as standard on a car,  but require additional costs for more technologies and these vary across the different manufacturers.

ADAS covers many technologies, each having a name describing their function. Many car manufacturers prefer to use their own terminology for these functions as part of their marketing strategy.


This has led to descriptions which imply a higher level of technology than is used.

Autopilot is one such example, it is a Level 2 function portraying a level 5 ability.

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