are hydraulically powered by means of a separate heavy duty hydraulic power pack with a large capacity fluid reservoir for increased reliability. The power pack and control gear is generally mounted in a steel roadside cabinet, and the actual lifting of the road blocker wedge is by means of hydraulic cylinders, mounted underground within the main structure of the road blocker. The fluid is transferred through large bore steel braided hydraulic hoses, which are professionally made to suit specific site requirements. The hydraulic power pack is available with either a single phase drive motor, or a three phase motor to allow very high frequency of operation. This is ideal for large car parks or busy sites.