(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: Provided that the Board shall, so far as may resonably be practicable, make adequate provision for-
(a) the passage of or diversion of traffic;
(b) securing access to all premises approached from such street; and
(c) any drainage, water supply, or means of lighting which is interrupted by reasons of the execution of the work.
(2) When any such direction has been give, the Board shall affix in a conspicuous place in or near the street an order prohibiting traffic to the extent so directed, and fix such bars, chains, or post across or in the street as it may think proper for ensuring compliance with the order.