Colorado is the earliest chain law state, starting September 1

Colorado winter tire chain law | CNS DOT compliance

Unpredictable weather systems can happen anytime, however snow often begins sticking to high-elevation routes in Colorado as early as mid- to late September.

According to Colorado Department of Transportation (CDOT), from Sept. 1 through May 31, all commercial vehicles traveling on I-70 between the Dotsero exit (mile point (MP) 133) and the Morrison exit (MP 259) must carry sufficient chains to be in compliance with the Colorado chain law.

For drivers and the public’s safety, it is important to use chains in compliance with Colorado’s chain law for commercial vehicles fitting into one of the following categories:

  • Vehicles with a gross combination weight rating of more than 26,000 pounds, inclusive of a towed unit, which has a gross vehicle weight-rating of more than 10,000 pounds
  • Vehicles with a gross vehicle weight rating of 26,001 or more pounds, or
  • Vehicles designed to transport 16 or more passengers, including the driver

The fine for not carrying chains on I-70 between mileposts 133 and 259 from September 1 to May 31 is $50 plus a $17 surcharge. Statewide, the fine for not chaining up when the chain law is in effect is $500 plus a $79 surcharge. The fine for not chaining up and subsequently blocking the highway is $1,000 plus a $157 surcharge.

At a minimum, the CDOT will notify the public of the travel restriction with erected static and electronic variable message roadway signs. Additionally, CDOT may utilize radio channels, the official CDOT travel website (, phone message system, email, text and other automated personal notification systems.

Tire Chains Allowed in Colorado:

Metal chains must consist of two circular metal loops–one on each side of the tire–connected by not less than nine evenly spaced chain loops across the tread. Commercial vehicles that have four or more drive wheels must chain four wheels and dual tire chains are acceptable.

Alternate Traction Devices
Approved Alternate Traction Devices (ATDs) in Colorado are:

  • wheel sanders, which carry enough sand to get the vehicle through the restricted area
  • pneumatically driven chains, which spin under the drive wheels automatically as traction is lost, and
  • textile traction device (TTD), a fabric boot which encompasses the tire. Currently, the only TTD that has been approved for use on Colorado state highways is the AutoSock.

Tire Cables
With only two exceptions, Colorado chain law rules do not permit tire cables as alternate traction devices.

Check out our industry library resources of 15 videos, 2 ebooks, industry links, and CNS In The News content.

The exceptions are:

  1. tire cables with high strength steel cross member rollers 0.415″ or greater in diameter, which can be used on all commercial vehicles except single drive axle combinations; and
  2. on a tandem power drive axle commercial vehicle, where any type of cable can be used only if there are chains on the two outside tires of one of the power drive axles and cables on two or more tires of the other power drive axle.


Colorado Chain Law Levels

There are two levels for chain laws in Colorado—Level 1/Code 17 and Level 2/Code 18—and each level has specific conditions in which it can be implemented.

Chain Law Level 1/Code 17:
All single-drive axle combination commercial vehicles must chain all four drive wheels; cables are not permitted as ATDs. All other commercial vehicles must have snow tires or chains.

Level 1/Code 17 may be implemented any time there is snow covering any part of the traveled portion of pavement on an ascending grade.

Chain Law Level 2/Code 18:
All commercial vehicles must chain up. Single drive axle combination and tandem drive axle commercial vehicles must chain four drive wheels.

Auto-transports must comply to the extent possible without causing damage to hydraulic lines. Buses must chain two drive wheels to be DOT compliant.

Level 2/Code 18 may be implemented any time there is snow covering the entire traveled portion of pavement on an ascending grade, or when driving conditions dictate that this level is necessary to protect safety and to minimize road closures.

Be sure to review our complete guide on extreme weather and regulations affecting drivers this season.

DOT Training

All fleets need to conduct proper and thorough pre and post trip inspections, which consists of implementing quality:

  • driver training that is ongoing and consistent
  • driver education, and
  • driver awareness of current and changing traffic laws

All of this will help prevent being targeted by the DOT at roadside inspections and is a valuable resource to ensure a healthy fleet, and compliant safety practices.

Our DOT trainers offer a variety of in-person or online training courses tailored to the specific needs or weaknesses of your company.

Questions about DOT Compliance, Licensing, Audits, Programs, etc.?

Our DOT Specialists are here to help!

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