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. 42-4-1701). CDOT can post the Commercial Motor Vehicle Chain Law on any state highway. It covers every vehicle of 16,001 pounds or more. A truck needs real chains or an approved device like AutoSock on at least four drive tires, and snow tires do not count. From September 1 to May 31, commercial vehicles of 16,001 pounds or more must carry chains on seven mountain corridors, including I-70 west of Morrison. Watch COtrip for the live order.

When, where, and what counts

• When required: No fixed storm calendar. CDOT switches the Passenger Vehicle Traction Law, Passenger Vehicle Chain Law or Commercial Motor Vehicle Chain Law on in real time by roadside sign, message board, and COtrip when a storm hits, and Colorado State Patrol enforces it (2 CCR 601-14 Rule 2.01). For trucks the order to watch for is the Commercial Motor Vehicle Chain Law. Separate from that, commercial vehicles over 16,000 pounds must CARRY chains or ATDs September 1 to May 31 on the seven carry corridors.
• 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 Commercial Motor Vehicle Chain Law or either passenger vehicle order on any state highway, and chain-up stations sit along the main mountain routes.
• Applies to: Every vehicle of 16,001 pounds or more falls under the posted Commercial Motor Vehicle Chain Law. It turns on weight rating, not use. It covers commercial motor vehicles with a GVWR or GCWR of 16,001 pounds or more used in commerce or built for 16 or more passengers including the driver, plus privately used trucks, truck tractors pulling trailers, and motor homes of 16,001 pounds or more (2 CCR 601-14 Rules 1.06, 5.01, 5.01.1). A hot-shot rig used for hire at 16,001 pounds or more counts as a commercial vehicle. The must-carry rule binds any commercial vehicle with a declared gross vehicle weight rating of 16,001 pounds or more (C.R.S. 42-4-106(5)(a)(I)(C)).
• Chains vs traction devices: The Commercial Motor Vehicle Chain Law 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 (2 CCR 601-14 Rule 5.02). Tire cables are not a free substitute for chains. A single drive axle vehicle, straight truck included, may not run cables at all (Rule 6.04.2). A tandem drive axle vehicle may use them only when the outer tires on both ends of one drive axle carry real chains and the cables go on the other drive axle, for at least four traction devices in total (Rule 6.04.1). Only an 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 the Commercial Motor Vehicle Chain Law, except under the auto transporter fallback in Rule 5.06.3. While it is in effect, vehicles of 16,001 pounds or more must stay in the right lane. You may pass in the left or center lane only around a stalled or slower vehicle that would cost you traction, only when it is safe, and you must finish the pass without losing traction and return to the right lane right away (Rule 5.05). A commercial vehicle hauling flammable, combustible, or explosive materials as defined by federal rules may drive past the chain-law signs until it meets snow on the road. It must then chain at the first safe spot off the traveled lanes where the pavement is mostly covered by snow or ice (Rule 5.03). The Passenger Vehicle Traction Law does not apply to vehicles of 16,001 pounds or more.
• Check the live order: COtrip.org and the COtrip Planner app for a live Commercial Motor Vehicle Chain Law or passenger vehicle order; the CSP chain-law page and CDOT Mountain Rules at freight.colorado.gov. Roadside signs and message boards show the active order.
• 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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