Patent ID: 7086805

Claim:
A crash attenuator comprising: a plurality of guiderails attached to the ground; an impact structure rotatably mounted on the plurality of guiderails; at least one mobile structure movably mounted on the plurality of guiderails behind the impact structure and capable of stacking with the impact structure upon a vehicle impacting the impact structure; a cylinder located between the guiderails, the cylinder including a piston rod extending from a first end of the cylinder; a first plurality of sheaves positioned at a second end of the cylinder; a second plurality of sheaves positioned at a first end of the piston rod; and a cable connected to the impact structure and looped around the first and second pluralities of sheaves, wherein the cable and cylinder apply to the impact structure a varying force to resist the impact structure translating away when impacted by a vehicle to thereby decelerate the vehicle at or below a predetermined rate of deceleration.