Prevention or restriction of traffic in street vested in Board during progress of work

(1) When any work which may lawfully be done is being executed by the Board in any street vested in it, the Board may direct that such street shall, during the progress of such work, be either wholly or partially closed to traffic generally or to traffic of any specified description. (2) When any such direction has been given, the Board shall put up, in a conspicuous position in or near the street, an order prohibiting traffic to the extent so directed, and fix such bars, chains or posts across or in the street as it may think proper for preventing or restricting traffic therein.