(o)[regulating the painting or marking of transport vehicles and the display of advertising matter thereon, and in particular prohibiting the painting or marking of transport vehicles] [Substituted by Act 100 of 1956, section 61, for 'prohibiting the painting marking or of a State or a contract carriage' (w.e.f. 16-2-1957).] in such colour or manner as to induce any person to believe that the vehicle is used for the transport of mails;