23-2-634. Regulation of snowmobile noise. (1) Except as provided in this section, every snowmobile must be equipped at all times with noise-suppression devices, including an exhaust muffler in good working order and in constant operation. A snowmobile may not be modified by any person in any manner that will amplify or otherwise increase total noise emissions to a level greater than that emitted by the snowmobile as originally constructed, regardless of date of manufacture.
     (2) Every person who owns or operates a snowmobile manufactured after June 30, 1972, but prior to June 30, 1975, shall maintain the machine in such a manner that it will not exceed a sound level limitation of 82 dbA measured at 50 feet.
     (3) A snowmobile manufactured after June 30, 1975, except snowmobiles designated for competition purposes only, may not be sold or offered for sale unless that machine has been certified by the manufacturer as being able to conform to a sound level limitation of not more than 78 dbA measured at 50 feet. Every person who owns or operates a snowmobile manufactured after June 30, 1975, shall maintain the machine in such a manner that it will not exceed a sound level limitation of 78 dbA measured at 50 feet.
     (4) A manufacturer who certifies that a new snowmobile can comply with the noise limitation requirements of 23-2-601 through 23-2-644 shall affix a permanent notice of that certification to every snowmobile offered for sale in the state of Montana.
     (5) In certifying that a new snowmobile can comply with the noise limitation requirements of 23-2-601 through 23-2-644, a manufacturer shall make the certification based upon measurements made in accordance with SAE recommended practice J192, as amended. The department, in enforcing the provisions of this section, shall make measurements of snowmobile noise in accordance with applicable practices outlined in the "Procedure for Sound Level Measurements of Snowmobiles" (January, 1969), as amended, used by the international snowmobile industry association or with other standards for measurement of sound level as the department may adopt.
     (6) This section does not apply to organized races or similar competitive events held on:
     (a) private lands or waters, with the permission of the owner, lessee, or custodian of the land or waters; or
     (b) public lands or waters, with the consent of the public agency having the authority to grant consent.

     History: En. Sec. 9, Ch. 434, L. 1971; amd. Sec. 2, Ch. 124, L. 1973; amd. Sec. 2, Ch. 91, L. 1974; amd. Sec. 1, Ch. 161, L. 1977; amd. Sec. 13, Ch. 417, L. 1977; amd. Sec. 14, Ch. 421, L. 1977; R.C.M. 1947, 53-1020(part); amd. Sec. 9, Ch. 363, L. 1979; amd. Sec. 7, Ch. 351, L. 1993.