When a collision could potentially happen, it lets drivers know with audio and visual alerts, and can even automatically apply the brakes if needed. (stevenscreektoyota.com)
There's also available cross traffic assist, which will use radar to detect cars and pedestrians, then automatically applying the brakes if a possible collision is detected. (topspeed.com)
These things involve poorer braking performance such as push back from the brake pedal or shaking of the steering wheel when applying your brakes and even noise. (cquence.net)