Abstract: A bumper has a ram (1) cooperating by a pressure fluid chamber (5) with a collision energy dissipating unit (11), in which kinetic energy of progressive motion is converted into kinetic energy of rotary motion. The pressure fluid chamber (5) is made as an angle fluid splitter (4) comprising an input cylinder (3) co-operating with a piston (2) of the ram (1) and at least two output cylinders (6, 7) angularly deviated from an axis (20) of the input cylinder (3), said output cylinders co-operating with pistons (9), the piston rods (10) of which are linked with the energy dissipating units (11) driving spinning masses (15).