ADAS (which stands for Advanced Driver Assistance System) is a vehicle safety system that brings together data from an array of sensors, these sensors are typically a combination of LiDAR (light detection and ranging), RADAR (radio detection and ranging) and cameras that are fitted to a vehicle with intelligent software working behind the scenes to detect and monitor hazards around the vehicle.
These hazards can be anything from a pedestrian to other stationary or moving vehicles, if an obstacle is detected, the assistance system will act to try and prevent an incident, for example, if your vehicle has ADAS with autonomous emergency braking and you're driving along a residential road when a car in front of you stops unexpectedly, the system will identify the obstacle, warn you of the hazard and then, if you've not acted quickly enough, apply emergency braking which will bring your vehicle to a stop.
These systems sound complicated and behind the scenes they are, but from a drivers point of view most of these systems are easy to use and make driving safer but as with any new technology, if you have a vehicle with ADAS fitted, it's important you understand what the system is and what that means for you in terms of vehicle maintenance.