4.—(1) The provisions of article 3 above shall apply only during such times and to such extent as may from time to time be indicated by traffic signs.
(2) The provisions specified in article 3 above shall not apply in respect of–
(i)any vehicle being used for the purpose of those works, or for fire brigade, ambulance or police purpose, or
(ii)anything done with the permission or at the direction of a police constable in uniform or a traffic warden.