Abstract: A protective device for a motor vehicle comprises an elongate guard member having a longitudinal axis oriented substantially parallel to the longitudinal axis of the vehicle. The guard member is variable in length between a contracted position and an extended position. A pivot assembly operatively connects the guard member to the underside of the vehicle so that the guard member can be moved between a lower position and an upper position along the side of the vehicle. As the guard member is raised to its upper position, the pivot assembly acts on the guard member to extend its length to its extended position, while lowering the guard member causes the pivot assembly to contract the guard member to its contracted position. The pivot assembly includes front and rear "L"-shaped pivot members each having a first arm rotatably mounted in a tube attached to the underside of the vehicle, and a second arm pivotably connected to a telescoping, sliding portion of the guard member.