My new 2012 Prius III was braking with the normal Prius noises until yesterday. It as 1,000 miles on it and while my wife was driving it on the highway a person cut in front of her so she had to brake hard to avoid them. Ever since then when I press on then brake normally I hear a thump noise and feel a vibration under my right foot (just to the left of the brake and on the floor). It comes when I brake at speeds greater than about 12 mph. Any idea what it is and why it started? I'm planning on taking it in to the dealer to get it checked out, but has anyone else had this experience?