a vehicle bumper system includes a bumper beam and a polymeric energy absorber positioned on a front of the bumper beam . the energy absorber has multiple box - shaped sections and also has interconnecting sections positioned along the length that interconnect adjacent ones of the box - shaped sections . the box - shaped sections of the energy absorber , when cross - sectioned by a transverse plane , include top and bottom u - shaped sections formed by top parallel legs and a top vertical leg and by bottom parallel legs and a bottom vertical leg , respectively . end walls close ends of the box - shaped sections and stabilize the top and bottom u - shaped sections . the interconnecting sections include a tying wall that connects the end walls together . by this arrangement , the box - shaped sections provide a stable and reliable energy absorbing mechanism .