??

Letting up on the brakes would increase your chance of whiplash.

Imagine that your brakes were so good that your car was completely immovable. If someone hit you from behind, it would crunch your car but you, personally, would not be affected.

Now imagine that your car weighs only 100 pounds with no brakes, and someone hits you from behind. Your car will accelerate nearly instantaneously to the speed of the vehicle that hit you, incurring very high G forces, in all likelihood breaking your neck.

tanstaafl.