This is for Ontario
Highway Traffic Act, R.S.O. 1990, c. H.8
Operating within permitted weight
121. (1) No vehicle or combination of vehicles having a permit issued in accordance with section 7 of this Act, the fee for which is based upon gross vehicle weight, shall be operated on any highway where the gross vehicle weight exceeds that for which the permit was issued. R.S.O. 1990, c. H.8, s. 121 (1); 1996, c. 9, s. 26.
Exception to subs. (1)
(2) Despite subsection (1) and subject to sections 116, 117 and 118, where a conversion unit is used to convert a two axle tractor into a three axle tractor and the fee prescribed in the regulations in respect of the conversion unit is paid, the vehicle or combination of vehicles to which the conversion unit is attached may operate on a highway at a maximum gross vehicle weight of 7,000 kilograms in excess of the gross vehicle weight for which a permit was issued for the vehicle or combination of vehicles in accordance with section 7 and the Ministry shall issue a receipt for the fee so prescribed and paid. R.S.O. 1990, c. H.8, s. 121 (2).
Receipt re excess weight payment to be carried
(3) The receipt issued by the Ministry in accordance with subsection (2) shall, whenever a vehicle is on a highway with the conversion unit referred to in subsection (2) attached, be carried by the driver of the vehicle or placed in some readily accessible position in the vehicle and shall be surrendered when demanded by a police officer or an officer appointed for carrying out the provisions of this Act. R.S.O. 1990, c. H.8, s. 121 (3); 2002, c. 18, Sched. P, s. 27.
Penalty
(4) Every person who contravenes subsection (1) is guilty of an offence and on conviction is liable to a fine as if the person had been convicted under section 125 and the Registrar may suspend the permit issued under section 7 for the vehicle or vehicles involved, and the suspension shall continue until a new permit at the maximum gross vehicle weight allowable has been issued for the vehicle or vehicles and the fee therefor has been paid. R.S.O. 1990, c. H.8, s. 121 (4).