Colo. Rev. Stat. § 43-1-226
It is declared to be the purpose of the general assembly in the passage of section 43-1-225 that the state of Colorado may more fully avail itself of the benefits of funds apportioned for expenditure on federal-aid primary or secondary systems and on the interstate system, including extensions thereof within urban areas, in conformance with the "Federal-Aid Road Act", approved July 11, 1916, and all acts of the congress amendatory thereof and supplementary thereto.
C.R.S. § 43-1-226
For the "Federal-Aid Road Act", actually titled "An act to provide that the United States shall aid the States in the construction of rural post roads, and for other purposes.", see 39 Stat. 355. For current provisions pertaining to the "Federal-Aid Road Act", see 23 U.S.C. §§ 101, 202, 204, 205.