Montana Can Require Chains at Any Time of Year
Date Published
Montana's chain rule is short, statutory, and carries no seasonal limit at all. The date range that appears in the same section belongs to a different subject.
The power
Mont. Code Ann. 61-9-406 subsection (6) provides that the department of transportation may determine at any time that dangerous or unsafe conditions on a highway require particular tires, tire chains or traction devices for vehicles in addition to or beyond ordinary pneumatic rubber tires.
At any time is the operative phrase. Montana holds high ground that can take snow well outside a conventional winter window, and the statute is drafted to match.
What has to be signed
Subsection (7) requires the department to place and maintain signs and other traffic control devices on a highway designated under subsection (6) indicating the requirement determined for vehicles. As in every chain-law state, the requirement binds through the sign rather than through the determination.
The same subsection sets the placement. Where the department determines that chains are required and that no other traction device will suffice, the requirement applies to tires on the driver wheels of one axle. Signs may differentiate in requirements for four-wheel-drive vehicles in gear.
The date range that is not about chains
Subsection (3) permits pneumatic tires embedded with material such as wood, wire, plastic or metal, provided the material does not protrude more than one-sixteenth of an inch beyond the tire tread, and limits their use to between 1 October and 31 May each year.
That is a studded and embedded tire rule. It is seasonal, and it sits a few subsections above the chain provision, which is why it is often reported as though Montana had a seasonal chain law. It does not.
The penalty
Subsection (8) provides that a violation of subsection (6) or (7) is subject to the penalties in 61-9-520, which treats it as the nonmoving offence of failure to use chains or approved traction devices when required.
Where the rule lives
Montana is one of three states, with Idaho and Wyoming, whose chain power is written into the vehicle code rather than an administrative rule. Searching the Administrative Rules of Montana for a chain law returns nothing useful. The provision is in Title 61, Chapter 9, among the vehicle equipment sections.