Which States Actually Have a Chain Law
Date Published
Nine states can require a commercial vehicle to fit chains: Colorado, Washington, Oregon, Nevada, Utah, Idaho, Montana, Wyoming and California. That is a much shorter list than most published tables suggest, and the reason is a drafting quirk that appears in almost every state vehicle code.
Permission is not obligation
Nearly every state carries a sentence in its equipment statute reading, in some form, that it is permissible to use tire chains of reasonable proportions upon any vehicle when required for safety because of snow, ice or other conditions tending to cause a vehicle to skid. That line comes from the Uniform Vehicle Code, and it appears in states with a chain law and states without one alike.
It grants a permission. It creates no duty. A state only has a chain law if something else gives an agency the power to compel chains, and that power lives in one of two places.
Where the duty actually comes from
In six of the nine states the duty is in an administrative rule issued by the transportation department: Colorado's 2 CCR 601-14, Washington's WAC 204-24-050, Oregon's OAR chapter 734 division 17, Nevada's NAC 484D.235, Utah's R920-6 and California's 13 CCR 1072.
In the other three the legislature wrote the trigger directly into the vehicle code: Idaho at section 49-948, Montana at 61-9-406, and Wyoming at 31-5-956. Searching only the administrative code in those three states finds nothing and produces the wrong answer.
The states that only permit
Arizona, New Mexico, Alaska, Pennsylvania, Minnesota, West Virginia and Virginia were each checked against their own equipment provision, and each one only permits. Arizona's is 28-958, Minnesota's is 169.72, West Virginia's is 17C-15-37 and Virginia's is 46.2-1044. Pennsylvania's 75 Pa.C.S. 4525(d) is the clearest of them: chains may be temporarily used during a snow and ice emergency. May, not must.
None of that means those states cannot close a road or restrict travel in a storm. It means they have no standing mechanism that turns chains into equipment you are required to be carrying.
What this changes for planning
If you run the northern tier or the Rockies in winter, the nine states above are the ones where a posted sign can stop you at a scale house for equipment rather than for weight. Everywhere else, chains are a tool you may choose to use. The distinction matters most when you are deciding what to keep on the truck in October.