Section 154(2) in The Bihar Motor Vehicles Rules, 1992
(2)Notwithstanding anything contained in sub-rule (1), (i) Passengers may be carried standing in the single decked stage carriage or on the lower deck of any double decked stage carriage if a fixed grab bar with hanger straps is provided in the roof over the gangway, (ii) Where such stage carriage is operated within the limits of a municipal corporation or a municipality constituted under any law for the time being in force in the State including an area within a radius of such kilometers from such limits, the Regional Transport Authority may direct that passengers may be carried standing in such public service vehicle if there is a clear space serving as a gangway of such greater width than that prescribed in Rule 156, as the Regional Transport Authority may specify in this behalf.