The biggest problem regarding the safety occupants during the rear-end collision is occurence of “Whiplash” phenomenon, which means that the human head moves backwards in relation of the thorax movement which is in the sitting position. In this case only the headrest opposes to the head movement. An important role in attenuation of this phenomena is played by the correct position of headrest relative to the head position. If the headrest is adjusted correctly, to limit the angle and movement of the head and neck during a rear-end collision, it should reduce the injury risk caused by “Whiplash”, phenomenon which can caused easy to dangerous injuries. This paper presents a comparative analysis during the rear-end collision between a driver with the headrest adjusted in optimal and wrong position.  The analysis is based on front quarter driver side of body car, using an anthropomorphic dummy. The quarter of car was positioned on a sledge that was located on the test stand. The data acquired during the tests were processed in order to evaluate the most common injury criteria, called HIC (Head Injury Criteria).