Abstract: A rear underride protection (1) intended for vehicles (2) comprising a bar (10) transversal to the direction of motion of the vehicle (2) and fixed to the vehicle (2), and a movable bar (13) displaceably arranged in the longitudinal direction of the fixed bar (10). At one end the movable bar (13) has a means of attachment (14) to enable fitting of an implement, e.g. in the form of a side-plough (3). The projection of the movable bar (13) can be adjusted at one's option and the sliding motion be effected by means of a double-acting hydraulic cylinder to which oil is supplied from the forced oil system of the vehicle (2). The hydraulic cylinder actuates the movable bar (13) by a buffer means, the purpose of which is to spare the rear underride protection (1) and implements connected to this great mechanical stresses.