Abstract: A road barrier comprising a support (101) to which a transverse beam (102) is connected via a spacer (110) such that upon impact the transverse beam (102) moves towards the support (101). The spacer (110) is movable upon impact and coupled, via coupling means (130, 150, 160, 170), with a rotatable energy absorber (140) mounted below the transverse beam (102) and comprising at least one rotor (142, 143) for absorbing in rotational movement at least part of the kinetic energy imparted to the transverse beam (102).

Abstract: The kinetic energy of a driving means (1) is converted into the kinetic energy of a rotor device with variable moment of inertia by bringing a rotor (4) into rotary motion, and furthermore the weight moved along a trajectory set by a guide (5) is brought by centrifugal force into additional rotary motion in relation to its axis. The rotor device contains a driving means (1) transmitting kinetic energy to a rotor (4) with variable moment of inertia with at least one guide (5), along which the weight increasing the moment of inertia moves by centrifugal force related to the rotation of the rotor (4), with the guide (5) of the rotor (4) having toothed driving surface (6), with which the toothed wheel (7) being the rotary weight is meshed.