Montana Title 61. Motor Vehicles § 61-9-321. Engine compression brake device--use

(1) A commercial motor vehicle equipped with an engine compression brake device must be equipped with a muffler in good working condition to prevent excessive noise.

(2) An operator of a commercial motor vehicle that has an engine compression brake device with a factory-installed muffler or an equivalent after-market muffler may not be prohibited from using the engine compression brake device.

(3) The department of transportation employees who are designated as peace officers pursuant to 61-10-154 shall work with law enforcement in the enforcement of standards adopted pursuant to this section.

(4) Notice of a deficiency must be given pursuant to 61-9-501.

(5) A violation of the rules adopted to implement to this section is punishable as provided in 61-9-521.