Abstract: A crash cushion including a cushion filled with material; and a back plate including at least one recess communicating with a back of the cushion such that material from the cushion fills the recess; wherein the back plate is configured so that when a force is applied to said cushion, the material within the at least one recess breaks a portion of the bumper plate and exits the recess. A crash cushion including a cushion filled with material; a back plate, including at least one opening communicating with a back of the cushion such that the material from the cushion is capable of filling the recess; and at least one valve; wherein the at least one valve is configured so that when a force is applied to the cushion, a portion of the material within the cushion opens the valve and exits the cushion.

Abstract: An energy absorbing device adapted to be connected between a motor vehicle bumper and a motor vehicle frame includes a liquid filled cylinder having a piston therein connected to the impact receiving device. The cylinder is provided with a plurality of weakened areas along the length of the cylinder which will rupture in sequence upon application of force by the piston to the liquid, thereby dissipating the force applied to the impact receiving means. A spring or an explosive device may be provided between the piston and closed end of the cylinder or the interior walls of the cylinder may be roughened to provide additional resistance to the movement of the piston within the cylinder. Additionally, the liquid expelled from the cylinder can be channeled through various devices to apply a reverse force to the impact receiving device.