Cal. Streets and Highways Code § 474

(a) Route 174 is from Route 80 near the City of Colfax to Route 20 near the City of Grass Valley. (b) (1) Upon the commission determining that it is in the best interests of the state to do so, the commission may, upon terms and conditions it approves, relinquish to the City of Grass Valley the portion of Route 174 within the city limits of the City of Grass Valley if the department and the City of Grass Valley enter into an agreement providing for that relinquishment. (2) A relinquishment under this section shall become effective on the date following the county recorder’s recordation of the relinquishment resolution containing the commission’s approval of the terms and conditions of the relinquishment. (c) On and after the effective date of the relinquishment, all of the following shall occur: (1) The relinquished portion of Route 174 shall cease to be a state highway. (2) The relinquished portion of Route 174 shall be ineligible for future adoption under Section 81. (3) The City of Grass Valley shall ensure the continuity of traffic flow on the relinquished portion of Route 174, including, but not limited to, any traffic signal progression. (4) For the relinquished portion of Route 174, the City of Grass Valley shall maintain signs within its jurisdiction directing motorists to the continuation of Route 174.