If you've been hurt by a truck driver who wasn't using chains in poor weather, you may have a case. Why? Chains are required at several times during the year. In Colorado, commercial vehicles must follow several rules.
These rules are in place to prevent injuries to other drivers caused by accidents and to help the drivers do their jobs more effectively. For example, were you aware that commercial drivers in Colorado must carry chains in their vehicles from Sept. 1 until May 31 if they are traveling on I-70? Between Morrison and Edwards, snow and ice can be a serious problem, so failing to have chains for their wheels or to help pull trucks once they've gone off the road can be a reflection of poor planning.
A commercial vehicle, as defined under the chain law, is any vehicle that weights 26,001 or more pounds including the towed unit of over 10,000 pounds. If the vehicle can carry 16 or more passengers, it also qualifies as a commercial vehicle. As autotransports are slightly different, they must chain their tires as much as possible without hindering the hydraulics.
Chains must be used on all four drive wheels on commercial vehicles. Cables aren't permitted. Any commercial vehicle that doesn't fit the above specifications must have snow tires or chains as well. This restriction goes into place any time snow covers any part of the pavement. Don't think you'll have to guess about chains on your tires; in fact, all drivers can be notified of the chain law being in effect by electronic message signs, 511 traveler information, media outlets and other means.
Source: Colorado Department of Transportation, "Commercial Vehicle Information" accessed Jan. 15, 2015