Twice, the car has autonomously braked when there was no threat to the car. The first time we were subsequently rear ended, though fortunately at low speed. There was cosmetic damage to the bumpers of both cars and the occupants were shaken up, but not injured. The second time the were driving at about 35mph when the car slammed on the brakes. Fortunately the following vehicle was not close and there was no collision. The occupants were again shaken up, but not injured. The "braking assistance" can be disabled, but only for the current trip. It is automatically reenabled the next time the car is started.