Depends on where the back car hits your car

If your car hits the middle of the other car, then that's your fault unless you can prove that car is over speeding, which is hard to prove.

If you car got hit by the back car in the middle or front, that's your fault too. Again unless you can prove that car is over speeding.

If your car got hit by  the back side(not left or right back corner), most likely you will win the case.

This means some cases if you drive more aggressively, immediately change the lane in front of the other car, the car on the back only can beep you. has no other choices. Another word, some cases more defensive drive style doesn't mean less accident.