Colorado Tire Chain Laws

How Colorado handles chains

$500 plus a $79 surcharge if you skip chains, $1,000 plus $157 if you block the road (C.R.S. 42-4-106). Colorado posts two orders. Code 15 (Traction Law) takes chains, an approved device like AutoSock, or adequate tires. Code 16 (Chain Law) means real chains on at least four drive wheels, and snow tires do not count. Carry chains September 1 to May 31 over 16,000 pounds. Watch COtrip for the live order.

When, where, and what counts

• When required: No fixed storm calendar. CDOT and Colorado State Patrol switch the Traction Law (Code 15) or Chain Law (Code 16) on in real time by roadside sign, message board, and COtrip when a storm hits. Separate from that, commercial vehicles over 16,000 pounds must CARRY chains September 1 to May 31.
• Where: I-70 from Morrison to Dotsero is the core corridor, plus CO 9, US-40, US-50, US-160, US-285, and US-550. CDOT can post it on any state highway, and chain-up stations sit along the main mountain routes.
• Applies to: The must-carry rule binds commercial motor vehicles over 16,000 pounds combined weight, plus vehicles built for 16 or more passengers. When Code 16 is posted it applies to those commercial vehicles on the highway.
• Chains vs traction devices: Code 16 requires real chains or an approved alternate traction device (ATD) on at least four drive-wheel tires, all of them if the vehicle has fewer than four, and two on a bus. Cable chains and AutoSock, EasySox, ISSE, and Alpha Trax count as approved ATDs. Snow tires alone do not satisfy Code 16. Code 15 is looser and accepts chains, an ATD, or adequate tires.
• Check the live order: COtrip.org and the COtrip Planner app for the live Traction or Chain Law order; the CSP chain-law page and CDOT Mountain Rules at freight.colorado.gov. Roadside signs and message boards show the active code.
• Fine: $500 plus a $79 surcharge for violating the chain law when it is in effect, and $1,000 plus a $157 surcharge if you get stuck and block any traveled part of the roadway. The penalty runs as a traffic infraction under C.R.S. 42-4-1701.

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