Audi Pre-Sense Basic and Audi Pre-Sense prepares you and your vehicle for a possible collision when it recognizes quick brake inputs or skidding to keep you safe, it then provides a warning, a quick brake application that would initiate brake assist, and then partial braking to slow your vehicle, then, if you have regular Audi Pre-Sense, a possible fourth step of stronger automatic braking. (paulmilleraudi.com)