Use the following trick to reverse at speeds greater than 500 mph. This only works for a manual transmission. Drive forward, staying in first gear. Then, slam the brakes and go into a reverse. Drive as fast as you can in reverse, then release L2 and press R2 (accelerator). As soon as you enter first gear, shift down to neutral (Right Analog-stick Down and keep holding R2). You will be accelerating in neutral and reach speeds of over 500 mph. This is useful for getting away from the police.