Cal. Streets and Highways Code § 438

(a) Route 138 is from: (1) Route 5 near Gorman to Route 14 near the City of Lancaster. (2) Route 14 near the City of Palmdale to Route 18 near Crestline. (b) (1) Upon a determination by the commission that it is in the best interests of the state to do so, the commission may, upon terms and conditions approved by it, relinquish to the City of Palmdale all or a portion of Route 138 within its jurisdiction, if the department and the city enter into an agreement providing for that relinquishment. (2) The following conditions apply upon relinquishment: (A) The relinquishment 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. (B) On and after the effective date of the relinquishment, the relinquished portion of Route 138 shall cease to be a state highway. (C) The portion of Route 138 relinquished under this subdivision shall be ineligible for future adoption under Section 81.