A motor vehicle bumper system comprising an outer shell (10) of an automotive bumper having an inner surface (18) generally oriented toward the vehicle. The outer shell comprises a plurality of energy absorbing protuberances (14) extending inwardly from the inner surface of the outer shell. The energy absorbing protuberances may be formed from an energy absorbing material, such as a polymeric foam, and/or may additionally comprise indentations extending into the body of the protuberance to enhance the energy absorbing characteristics of the protuberance.