Section 29(m) in The Bihar Motor Vehicles Rules, 1992
(m)Shall in the event of the vehicle being unable to proceed to its destination on account of mechanical break down or other causes beyond his control, arrange to convey the passengers to their destination in some other similar vehicle, or, if unable to arrange within a period of an hour after failure to proceed to the destination, shall on demand, refund to each passenger a proper proportion of the fare relating to the completion of the journey for which the passenger had paid the fare.
