4.—(1) The Department shall carry out such works as the Department considers necessary for the provision of a1ternative facilities for road traffic and on completion of the works the roads described in Part IV of the Schedule shall be stopped-up to road traffic at the lines, junctions and points specified in that Part.
(2) The Department shall carry out such works as it considers necessary to prevent or restrict to such extent as the Department thinks fit, access to the roads by road traffic.