I can understand how the inattentive driver would benefit from the stopped car adjusting the breaks to absorb the impact over a couple yards, but I'd like to see some analysis as to how this changes the injury risk for the passengers stopped car. My first thought is that pushing harder on the brakes could force most of the energy into crumpling the structure of the stopped car rather then into accelerating the stopped car. This could reduce the force on the passengers. My theory is that the brakes should be applied hard in the beginning of the crash to minimize any acceleration of the previously stopped car and then reduced after max speed is reached to minimize deceleration of the car.