2023 Montana Code Annotated › Title 61. Motor Vehicles › Chapter 10. Size -- Weight -- Load › Part 1. Standards, Permits, and Fees › 61-10-102. Width -- definitions

61-10-102. Width -- definitions.
(1) Except as provided in subsections (2) and (3), a vehicle, including a bus, unloaded or with load, may not have a total outside width in excess of 102 inches. This width for buses is allowed only on paved highways 20 feet or more in width.
(2) (a) Subsection (1) does not apply to an implement of husbandry or a vehicle used for hauling hay that is moved or propelled upon the highway during daylight hours for a distance of not more than 100 miles if the movement is incidental to the farming operations of the owner of the implement of husbandry or the vehicle used for hauling hay. If the implement or vehicle is more than 12 1/2 feet wide, it must be preceded by flag vehicle escorts to warn other highway users. This restriction does not apply to dual-wheel tractors under 15 feet overall width that are used in farming operations or to movement on a county road within 100 miles of the farming operation of the owner of an implement of husbandry or a vehicle used for hauling hay. Lights that meet the requirements of 61-9-219(4) must be displayed on the rear of the implement of husbandry or vehicle used for hauling hay. However, if the highway passes through a hazardous area, the implements or vehicles must be preceded and followed by flag vehicle escorts unless the movement of the implements or vehicles is restricted to a county road within 100 miles of the farming operation of the owner.
(b) An implement of husbandry or a vehicle used for hauling hay that exceeds 16 1/2 feet in width and that is traveling on an interstate or a four-lane highway must be followed by a flag vehicle escort.
(c) A commercial vehicle that is hauling hay but does not qualify under subsection (2)(a) may be granted a permit subject to the provisions of 61-10-121 through 61-10-127.
(d) Subsection (1) does not apply to a commercial hay grinder moved or propelled upon the highway during daylight hours for a distance of not more than 100 miles if the movement is incidental to operations of the commercial hay grinder. A commercial hay grinder exceeding 102 inches in width must have a permit issued under 61-10-124. If the commercial hay grinder is more than 12 1/2 feet wide, it must be preceded by flag vehicle escorts to warn other highway users. Lights that meet the requirements of 61-9-219(4) must be displayed on the rear of the commercial hay grinder. Movement of a commercial hay grinder that does not exceed 138 inches in width may occur on any day of the week, including holidays, and is restricted to movement during daylight hours. Movement of a commercial hay grinder may not exceed the posted speed limit, including the speed limit on an interstate highway.
(3) (a) The width of a recreational vehicle, as defined in 61-1-101, and a camper, as defined in 61-1-101, that is being operated for noncommercial purposes may exceed 102 inches if:
(i) the excess width is attributable to recreational vehicle or camper appurtenances that do not extend beyond the exterior rearview mirrors of the recreational vehicle, the camper, a vehicle being towed by the recreational vehicle, or the motor vehicle providing motive power; and
(ii) the rearview mirrors extend only the distance necessary to provide the appropriate field of view for the vehicle before the recreational vehicle or camper appurtenances are attached.
(b) For the purposes of this section, "recreational vehicle or camper appurtenances" means an awning and its support hardware or any appendage that is intended to be an integral part of the recreational vehicle or camper and that is installed by the manufacturer or dealer.
(4) A safety device that the department determines by rule adopted pursuant to 61-9-504 to be necessary for safe and efficient operation of motor vehicles is not included in the calculation of width provided in subsection (1).
(5) Except as provided in subsections (2)(a) and (2)(b), a rear flag vehicle escort is not required for a vehicle that exceeds 12 1/2 feet in width, that is hauling or towing an implement of husbandry, construction equipment, or forestry equipment, and that is operating under this section or as authorized by special permit issued under 61-10-121 through 61-10-125 if the vehicle is operating at highway speed or with the flow of traffic.
(6) For the purposes of this section, the following definitions apply:
(a) "Construction equipment" means any vehicle, machine, or attachment designed or adapted for and used in construction, heavy construction, highway construction, and remodeling work.
(b) "Flag vehicle" means a vehicle equipped as required by law or by department of transportation rule to warn or guide vehicular traffic. When not being operated as a flag vehicle, signs must be removed.
History: En. 32-1123.3 by Sec. 14, Ch. 316, L. 1974; amd. Sec. 1, Ch. 314, L. 1975; R.C.M. 1947, 32-1123.3; amd. Sec. 74, Ch. 421, L. 1979; amd. Sec. 1, Ch. 109, L. 1983; amd. Sec. 1, Ch. 340, L. 1989; amd. Sec. 1, Ch. 413, L. 1993; amd. Sec. 1, Ch. 283, L. 1997; amd. Sec. 2, Ch. 449, L. 1999; amd. Sec. 4, Ch. 241, L. 2005; amd. Sec. 224, Ch. 542, L. 2005; amd. Sec. 1, Ch. 210, L. 2011; amd. Sec. 1, Ch. 115, L. 2023.