(COLO) – With weather forecasts including 70 and 80-degree temperatures on the Front Range, it’s hard to imagine potential snowfall in Colorado’s high country. Yet, summer snow is not that unusual at higher elevations in our state. That’s why, each year, from September 1 to May 31, Colorado’s Chain Law and Passenger Vehicle Traction law takes effect for all drivers. The Colorado Chain Law applies to more than just large commercial vehicles.
“Whether a tractor-trailer or a four-door sedan, snow and ice conditions impact your drive,” stated Col. Matthew C. Packard, chief of the Colorado State Patrol. “If carrying chains or checking your tire tread seems like a hassle, imagine the inconvenience of sitting in traffic due to a crash or being rerouted miles out of your way due to highway closures.”
According to Colorado’s current chain law, all vehicles must be prepared with adequate tires and equipment when traveling in Colorado during the winter. Here is what you need to know based on your vehicle type:
Larger Vehicles, Including Recreational and Commercial Motor Vehicles
As of August 7, 2024, all commercial motor vehicle drivers must carry chains from September 1 to May 31. This applies to vehicles with a combined weight of more than 16,000 pounds used in commerce or as a means of transport for at least 16 passengers (including the driver) on public highways.
Commercial vehicles and buses have a larger footprint on roadways where chains are required. CMVs must carry chains or ATDs on all the following roads regardless of current weather:
- I-70 west of milepost 259 (Morrison) to the Utah border.
- Colorado Highway 9 milepost 63 to milepost 97 (Frisco to Fairplay).
- Route 40 milepost 256 (Empire) to the Utah border.
- U.S. Route 50 milepost 225 (Salida) to the Utah border.
- U.S. Route 160 milepost 304 (Walsenburg) to the New Mexico border.
- U.S. Route 285 milepost 250 (Morrison) to the New Mexico border.
- All of U.S Route 550.
The penalty for non-compliance with winter driving restrictions: Up to a $500 fine plus a $79 surcharge, or, if you are stuck and blocking any traveled portion of the roadway, the fine is $1,000 plus a $157 surcharge.
Smaller Vehicles, including two-wheel and four-wheel drive
All motor vehicles with a GCWR/GVWR less than 16,001 pounds traveling on any portion of I-70 between mile point 259 (Morrison) and mile point 133 (Dotsero) from September 1 through May 31 must have:
- Tire chains for two or more drive tires; or
- An approved ATD for two or more drive tires; or
- Tires with a tread depth of at least 3/16-inch and which are rated for either “All weather” or “Mud and Snow” (indicated by a “All Season”, M+S, M/S, etc. on sidewall) by the manufacturer. This is indicated on the side of the tire by “M+S”, “M/S” or an icon of a mountain with a snowflake.
The penalty for non-compliance: $50 fine plus a $17 surcharge.
First CSP Commercial Motor Vehicle Chain Check Announced
With chain law season in effect, the Colorado State Patrol will be holding a CMV Chain Check Operation on Thursday, September 4, 2025, on I-70 near Dotsero. The primary focus of this event will be to enforce Colorado's must-carry chain law. Chain check operations are held when the weather is not expected to be inclement. This ensures commercial and private drivers are prepared at all times as required by Colorado law.
Chain law restrictions are announced through the Colorado Department of Transportation (CDOT). At a minimum, they will notify the public on static and electronic variable message roadway signs. Additionally, this information is regularly announced through 511 traveler information, the official CDOT travel website (www.cotrip.org), and various media outlets.
###
ABOUT THE COLORADO STATE PATROL
Since our origin in 1935, the Colorado State Patrol (CSP) has focused on preserving human life and protecting property within our communities. Our 1,100 members embody the core values of Honor, Duty, and Respect in their daily jobs. In addition to our expertise in motor vehicle safety on the state’s roadways, the CSP is responsible for the protection of the Governor and other dignitaries, commercial motor vehicle enforcement, hazardous materials, homeland security, communications, investigative services, criminal interdiction, community education, aviation operations, and more. For additional information, visit us online at Colorado State Patrol or follow us on X, Instagram, YouTube, or Facebook.