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 west of milepost 259 at Morrison to the Utah line is the core corridor, plus CO 9 from milepost 63 to 97 (Frisco to Fairplay), US-40 west of milepost 256 (Empire), US-50 west of milepost 225 (Salida), US-160 west of milepost 304 (Walsenburg), US-285 west of milepost 250 (Morrison), and US-550 from milepost 0 to 130. Those are the roads the carry rule covers (C.R.S. 42-4-106(5)(a)(I)(C)). I-70 between Dotsero at milepost 133 and Morrison is the passenger vehicle traction corridor, not the commercial one. CDOT can post the Traction or Chain Law 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. Tire cables are not a free substitute for chains. A single drive axle combination may not run cables at all. A tandem drive axle combination may use them only when the outer tires on both ends of one drive axle carry real chains, for at least four traction devices in total. A straight truck or auto transporter may run four cables of 0.415 inches or greater. AutoSock, EasySox, ISSE, and Alpha Trax are approved ATDs, but you may not use AutoSocks and cables together, and clip-on chains are never permitted. 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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