At low speeds, the overhead picture of your car (below the speedometer) will show lines where it detects obstacles. They start out light yellow, then turn dark yellow, orange and finally red. The distance to the obstacle is also shown. When you are just about to hit something it says STOP. It will also beep at you, unless you've muted it, which by the way is a little icon in the upper right of that display that looks like a speaker (everyone always asks what that is).