Montana Oversize and Overweight Fines and Penalties

All vehicles except passenger cars and pickup trucks under 14,000 lbs are required to stop at open Montana Weigh Stations. Any vehicle that weighs more than 10,000 lbs may be stopped for inspection and weighing at portable scale locations. (1) The operator is subject to the penalties stated in 61-10-232 whenever the gross loaded weight of any trucks, truck tractor, trailer, or semitrailer operated upon any highway in this state exceeds the gross vehicle weight shown on:

(a) the owner's certificate of registration and registration receipt issued under 61-3-322; or (b) the gross vehicle weight license issued under this part.
(2) In addition, the operator shall immediately pay to the nearest county treasurer or to the

department the difference between the fee already paid and that applicable to the gross weight of the vehicle before unloading the excess, provided that it does not exceed the legal axle weight. Any owner or operator of a motortruck, truck tractor, trailer, semitrailer, bus, or automobile who violates any provision of this part is guilty of a misdemeanor and shall be punished by a fine of not more than $300 or by a sentence of not more than 60 days in the county jail or both.

https://www.mdt.mt.gov/other/webdata/external/mcs/PERMIT-RESTRICTIONS.PDF