Chain Laws in Wyoming

Two Levels, Clear Consequences

Wyoming operates a straightforward two-level chain law system. Unlike Colorado’s three separate chain and traction laws, Wyoming keeps it simple: conditions are either hazardous or extremely hazardous, and your requirements change accordingly.

Level 1 vs. Level 2

Level 1 (Hazardous Conditions)

When WYDOT declares Level 1, you need one of: tire chains, adequate snow tires, or all-wheel drive. For commercial vehicles, chains must be installed on at least two drive wheels at opposite ends of the same axle.

Level 2 (Extremely Hazardous Conditions)

Level 2 narrows your options. Snow tires alone are no longer sufficient. You need either tire chains or AWD equipped with M+S (mud and snow) rated tires. The CMV chain requirement remains the same — two drive wheels at opposite ends of the same axle.

Chain-Up Areas

Three Sisters (I-80 MP 7-34)

The Three Sisters section of I-80 in southwest Wyoming between Evanston and Bridger Valley is the primary chain law zone on the interstate. Designated chain installation and removal areas exist at both ends of the section. This area combines elevation, exposure, and the wind conditions that define I-80 to create challenging winter driving.

Teton Pass (WY 22)

Teton Pass carries a 60,000 lb vehicle weight limit and features steep grades near Jackson Hole. Chain requirements apply during winter conditions, and the pass is a significant challenge for the vehicles that are allowed to use it.

No “Must Carry” Season

Unlike Colorado, which requires CMVs to carry chains from September 1 through May 31 under the 2024 Must Carry Law, Wyoming has no fixed must-carry season. Chain requirements activate based on current conditions, not the calendar.

This does not mean you should skip carrying chains. Any trucker running Wyoming I-80 between October and April without chains in the truck is gambling with both safety and operational continuity. When chain law activates at the Three Sisters and you do not have chains, you are stopped until conditions improve or you find chains.

Penalties

The $750 penalty for causing a closure is Wyoming’s way of saying: your decision to ignore the chain law costs everyone. When a truck without chains blocks I-80, the closure affects hundreds of vehicles. The fine is the smallest part of the cost — the carrier’s liability for blocking a major interstate is far greater.

Chain Law and Insurance

Chain law violations become part of your safety record and affect CSA scores. But the real insurance implication is the accident that chain law compliance prevents. A truck without adequate traction on the Three Sisters or Teton Pass that causes a multi-vehicle incident faces claims that dwarf the $250 fine. Proper Wyoming trucking insurance with adequate limits is the financial backstop, but compliance with the chain law is the first line of defense.

Do not stop in the driving lane to install or remove chains. Use designated chain-up areas only. Stopping in a travel lane on I-80 in reduced visibility creates the exact kind of incident that generates catastrophic claims.