What Is Colorado's Traction Law?
Colorado’s Traction Law gives the Colorado Department of Transportation (CDOT) authority to require specific tire and traction equipment on state highways during winter weather conditions. The law is designed to reduce crashes, spinouts, and traffic delays that occur when vehicles lack adequate traction on icy or snow-packed roads.
Under Colorado Revised Statutes § 42-4-106, CDOT can restrict highway travel to vehicles equipped with appropriate traction devices, winter-rated tires, or chains. When the law is active, drivers who fail to comply face fines and can be held responsible for blocking traffic.
The Traction Law applies to all passenger vehicles with a Gross Vehicle Weight Rating (GVWR) or Gross Combined Weight Rating (GCWR) under 16,001 pounds. This includes most cars, crossovers, SUVs, and light trucks.
Key Takeaways
- The Traction Law is in effect September 1 through May 31 on I-70 between Morrison and Dotsero, and can be activated on any state highway when conditions warrant
- 4WD and AWD vehicles need winter-rated tires with at least 3/16-inch tread depth, or chains/ATDs
- 2WD vehicle requirements are subject to pending legislative clarification; current enforcement allows compliance with proper winter tires or chains/ATDs
- Violations result in fines of $67 to over $1,000 depending on circumstances
- Rental car companies must notify customers about traction law requirements
- Check COtrip.org before traveling for current road conditions and active restrictions
Where and When Is the Traction Law in Effect?
September 1 through May 31
The Traction Law is automatically in effect from September 1 through May 31 on the I-70 Mountain Corridor between Morrison (Mile Post 259) and Dotsero (Mile Post 133). This stretch of highway connects the Denver metro area to popular ski resorts and mountain communities.
CDOT can also activate the Traction Law on any state highway at any time when weather or road conditions warrant. Drivers are notified of an active Traction Law through highway signage, electronic variable message signs, COtrip.org, and automated alert systems.
When you see signs indicating the Traction Law is in effect, you must comply immediately. Proceeding without proper equipment is unlawful under Colorado law.
Traction Law Requirements by Vehicle Type
Colorado’s Traction Law requirements vary depending on your vehicle’s drivetrain. The law places significant emphasis on tire condition and type, requiring specific ratings and minimum tread depth for compliance.
Requirements for 4WD and AWD Vehicles
When the Passenger Vehicle Traction Law is active, drivers of four-wheel-drive (4WD) and all-wheel-drive (AWD) vehicles must have one of the following:
- Winter tires with the mountain-snowflake icon and a minimum tread depth of 3/16 inch
- Mud and snow tires marked M+S, M/S, or M&S with a minimum tread depth of 3/16 inch
- All-weather rated tires (as designated by the manufacturer) with a minimum tread depth of 3/16 inch
- Tire chains or an approved alternative traction device (ATD) installed on two or more drive tires
If your 4WD or AWD vehicle has adequate tires meeting these specifications, you can travel without installing chains. However, the tires must have at least 3/16-inch tread depth across the entire tire surface.
Requirements for 2WD Vehicles
Note: Colorado legislators have indicated they will clarify the statutory language regarding two-wheel-drive vehicles in 2026. The information below reflects current enforcement guidance from the Colorado State Patrol.
Two-wheel-drive (2WD) vehicles, including front-wheel-drive cars, face stricter requirements under the Traction Law.
Must-Carry Requirement: From September 1 through May 31, all 2WD vehicles traveling on the I-70 Mountain Corridor should carry tire chains or an approved alternative traction device.
When Traction Law Is Active: According to current Colorado State Patrol enforcement guidance, 2WD vehicles can comply with the Traction Law by having either:
- Snow tires or M+S tires with adequate tread depth (3/16 inch minimum), OR
- Tire chains or an approved ATD installed on two or more drive tires
The State Patrol recommends that 2WD drivers install winter-rated tires so they can remain compliant when the Traction Law is in effect without needing to stop and install chains.
Legislative Update Expected: The sponsors of Senate Bill 25-069 have acknowledged that the current statutory language regarding 2WD vehicles needs clarification. The Colorado Legislature is expected to address this in the 2026 session. We will update this page when new guidance becomes available.
For the most current enforcement information, check the Colorado State Patrol website at csp.colorado.gov.
Understanding the Chain Law (Code 16)
The Passenger Vehicle Chain Law is the most restrictive winter driving requirement and serves as the final safety measure before CDOT closes a highway.
When the Chain Law is in effect, every passenger vehicle must have chains or an approved alternative traction device installed on two or more drive tires. This applies regardless of drivetrain type, including 4WD and AWD vehicles.
If you see signs indicating the Chain Law is active, conditions are severe. Consider finding a safe place to pull over or exit the highway, as closures typically follow soon after.
Approved Alternative Traction Devices
CDOT maintains an Approved Products List of alternative traction devices that can be used in place of traditional metal chains. Approved ATDs include:
| Product Type | Product Name | Manufacturer |
| Tire Sock | AutoSock | McGee Company |
| Tire Sock | EasySox | Quality Chain Corporation |
| Tire Sock | ISSE Tire Sock | Titan Chain & Supply, LLC |
| Cable Chain | Alpha Trax | Laclede Chain Manufacturing Company |
Alternative traction devices like tire socks are often easier to install than traditional chains and can be stored compactly in your vehicle. The full list of approved products is available at apl.codot.gov.
Fines for Traction Law Violations
Drivers who violate the Traction Law face financial penalties:
| Violation | Fine |
| Non-compliance with Traction Law | $50 fine + $17 surcharge ($67 total) |
| Blocking roadway due to inadequate equipment | Up to $500 fine + $79 surcharge |
| Blocking roadway (enhanced) | Up to $1,000 fine + $157 surcharge |
Beyond fines, drivers who cause delays due to inadequate equipment can face liability for damages. Spinouts and crashes on I-70 have caused traffic backups lasting nine hours or more during peak winter travel periods.
Rental Car Considerations
Out-of-state visitors and rental car drivers are a significant focus of Colorado’s Traction Law enforcement. According to Colorado State Patrol, a disproportionate number of traction violations and winter crashes involve rental vehicles driven by visitors unfamiliar with mountain conditions.
Under SB25-069, rental car companies in Colorado are encouraged under recent legislation and enforcement guidance to notify customers of traction law requirements before they drive away. Some companies have begun placing notification tags on rearview mirrors indicating whether a vehicle is Traction Law compliant.
If you are renting a vehicle in Colorado during winter months:
- Request a 4WD or AWD vehicle to maximize compliance options
- Verify the vehicle has M+S, all-weather, or winter-rated tires with adequate tread depth
- If renting a 2WD vehicle, carry chains or an approved ATD
- Review your rental agreement regarding the use of traction devices
Most rental car companies allow tire chains or ATDs when required by law, but policies vary. Review the fine print before your trip.
How to Check Your Tires for Compliance
To comply with the Traction Law, your tires must meet two criteria: proper rating and adequate tread depth.
Checking Tire Rating
Look at the sidewall of your tires for one of these designations:
- M+S, M/S, or M&S (Mud and Snow)
- Mountain-snowflake icon (Three-Peak Mountain Snowflake symbol)
- All-weather rating from the manufacturer
All-season tires typically have M+S markings. Dedicated winter tires display the mountain-snowflake icon.
Checking Tread Depth
Colorado law requires a minimum tread depth of 3/16 inch (approximately 4.8mm). You can check tread depth using the quarter test:
- Insert a quarter into your tire tread with Washington’s head facing down
- If the top of Washington’s head is visible, your tread may be too shallow for compliance
- For greater precision, use a tread depth gauge
CDOT recommends checking tread depth at multiple points around each tire, as wear can be uneven.
Commercial Motor Vehicle Chain Law
Separate requirements apply to commercial motor vehicles (CMVs) with a GVWR or GCWR over 16,001 pounds. Under Colorado’s “Must Carry Law” (SB24-100), CMV drivers must carry chains or approved ATDs from September 1 through May 31 on designated mountain corridors.
CMV chain requirements apply to:
- I-70 west of Morrison (MP 259) to the Utah border
- Highway 9 from Frisco to Fairplay (MP 63 to MP 97)
- US Route 40 from Empire (MP 256) to the Utah border
- US Route 50 from Salida (MP 225) to the Utah border
- US Route 160 from Walsenburg (MP 304) to the New Mexico border
CMV violations carry higher fines, with penalties up to $500 for not carrying chains and up to $1,000 plus surcharges for blocking the roadway.
Staying Informed About Road Conditions
Before traveling Colorado’s mountain highways during winter, check current road conditions and any active traction restrictions:
- COtrip.org provides real-time road conditions and camera feeds
- 511 (phone) offers automated road condition information
- CDOT social media (@ColoradoDOT) posts travel alerts
- Text and email alerts are available through subscription.cotrip.org
When winter storms are forecast, consider delaying travel until conditions improve. CDOT and the Colorado State Patrol strongly encourage drivers to avoid travel during the height of severe storms.
The Impact of Traction Violations on Accident Claims
Drivers who are involved in crashes while violating the Traction Law may face legal consequences beyond traffic fines. Proceeding without required equipment when a restriction is in effect demonstrates a failure to exercise reasonable care.
In personal injury cases arising from winter weather crashes, evidence that a driver lacked proper traction equipment can support claims of negligence. Conversely, drivers injured by others who were non-compliant with the Traction Law may have stronger claims for compensation.
If you have been injured in a crash involving a driver who lacked proper winter equipment, or if you have questions about how Colorado’s Traction Law may affect your legal situation, our attorneys can help you understand your options.
This article provides general information about Colorado’s Traction Law based on current statutes and CDOT guidance. The Colorado Legislature is expected to clarify certain provisions in 2026, and this page will be updated when new guidance becomes available. For the most current requirements, consult CDOT at codot.gov or the Colorado State Patrol at csp.colorado.gov.
About Ramos Law
Ramos Law represents Colorado drivers and families injured in motor vehicle crashes, including winter weather accidents on I-70 and other mountain highways. Led by Joseph Ramos, MD, JD, our team combines medical expertise with legal advocacy to build strong cases for full compensation.
If you have been injured in a crash and have questions about your legal options, contact us for a free consultation.
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