A crash barrier system is provided that generally includes a hydraulic actuator driven piston operably connected to a hydraulic circuit and the crash barrier. In general, the hydraulic circuit includes a normal-UP and normal-DOWN section, an emergency-UP section, and an external pressure relief valve. In order to automatically provide corrective action in the event of an overpressure condition, the external pressure relief valve is connected to the hydraulic circuit. Upon occurrence of condition that causes the hydraulic fluid pressure to exceed a predetermined value, hydraulic fluid is released through the pressure relief valve to maintain the pressure at or below the predetermined value.