Section 128 in The Bihar Motor Vehicles Rules, 1992
128. Prohibition of painting or marking of transport vehicle in certain manner.
(1)No advertising device, figure or writing shall be exhibited on any transport vehicle save as may be specified by the Regional Transport Authority by general or special order.(2)A transport vehicle when regularly used for carrying Government mail by or under a contract with the Indian Posts and Telegraphs Department, shall be painted in postal red colour and shall exhibit in a conspicuous place upon a plate or on a plain surface of the motor vehicle the word "MAIL" in red colour on a white ground, each letter being not less than 15 centimeters in height and of a uniform thickness of 20 millimetres.(3)Same as aforesaid no stage carriage or contract carriage shall be painted in postal red colour or display any sign or inscription which includes the word "MAIL":Provided that a stage carriage belonging to the State Transport Undertakings may be partly colour in red, if such colour is of a shade distinct from that used on vehicles carrying Government mail.
