The I-70 Colorado chain law is vital for winter safety. Truckers must follow this rule to avoid accidents and citations. Between Dotsero and Morrison , trucks over 26,000 pounds GVW must carry chains from September through May . When the chain law is active, drivers must install chains before climbing mountain grades. Violating this can lead to a $500 citation or a $1,000 fine if traffic is blocked. These laws are enforced to prevent accidents, improve traction, and keep highways open during extreme weather.