Section 94(9) in The Bihar Motor Vehicles Rules, 1992
(9)Plates. - (a) A plate of suitable size and pattern shall be attached to the meter or its gear-box in such a manner that it cannot be removed without either removing the seals affixed by the testing institute of opening the meter or the gearbox. The plate shall bear raised or sunken words, or figure denoting the measurement of the effective circumstances of the wheel by which the meter will be driven and by which its action and accuracy may be tested.(b)The measurements shown on the plate shall be in accordance with the circumstances of the wheels of minimum size approved for the cab and normally attached thereto.Explanation. - The effective circumstance of the cab wheel to which the meter transmission gearing is attached and by which the meter is driven is the distance which the cab moves forward for one complete revolution of the wheel and may be measured by making a mark on the tyre of the wheel where it touches the ground and punishing the motor cab in a straight line until this mark is again in contact with the ground, the motor cab being in its normal working condition and carrying two passengers.
