Wyo. Stat. Ann. § 24-10-112

In the event the general requirements of title 23, United States Code, "Highways", or existing rules and regulations of the United States department of transportation become amended or changed to less restrictive conditions than presently exist, then, the commission is empowered to amend or change such rules and regulations that they may have adopted to come into conformity with the federal law, rule and regulation; however, in no event shall this act become more restrictive than is indicated herein by said federal action.