C.R.S. § 43-4-203

(1) All net revenue from the following sources shall be paid into and credited to the highway users tax fund as soon as it is received: (a) From the imposition of any excise tax on motor fuel; (b) From the imposition of annual registration fees on drivers, motor vehicles, trailers, and semitrailers, except as provided in section 42-3-304 (19), C.R.S.; (c) From the imposition of passenger-mile taxes on vehicles or any fee or payment substituted therefor; (d) Repealed. (e) From interest or income earned on the deposit and investment of moneys in the fund; (f) From the imposition of electric motor vehicle road usage equalization fees pursuant to section 42-3-304 (25)(a.5); and (g) From the imposition of road usage fees pursuant to section 43-4-217 (3) and (4).