We can increase the efficiency of reactionary driving as much as we want with computers, but for me, you just can't beat defensive driving.
Just curious, How well do these systems handle potential rear threats as well? How would it handle tailgaters? Some tailgaters are more aggressive than others. Some just need a friendly reminder that you do not appreciate the tailgating by a nice easy slow down, or a slight tapping of the breaks. Others -- such as the guy in F250 super duty with 30 inch tires and a lift kit, you might just want to go ahead and move over when you see them coming.