Cal. Streets and Highways Code § 464

(a) Route 164 is Rosemead Boulevard from: (1) Gallatin Road near Pico Rivera to the southern city limit of South El Monte in the vicinity of Rush Street. (2) The southern city limit of South El Monte in the vicinity of Rush Street to the southern city limit of El Monte in the vicinity of the Rio Hondo River. (3) The southern city limit of El Monte in the vicinity of the Rio Hondo River to the southern city limit of Temple City in the vicinity of Grand Avenue. (4) Route 210 to Foothill Boulevard in the City of Pasadena. (b) The relinquished former portions of Route 164 within the County of Los Angeles and the City of Temple City are not state highways and are not eligible for adoption under Section 81. For the relinquished former portions of Route 164, the County of Los Angeles and the City of Temple City shall maintain within their respective jurisdictions signs directing motorists to the continuation of Route 164. (c) (1) Notwithstanding subdivision (a), the commission may relinquish to the County of Los Angeles that portion of Route 164 described in paragraph (1) of subdivision (a), pursuant to the terms of a cooperative agreement between the county and the department, upon a determination by the commission that the relinquishment is in the best interests of the state. (2) A relinquishment under this subdivision shall become effective immediately following the recordation by the county recorder of the relinquishment resolution containing the commission’s approval of the terms and conditions of the relinquishment. (3) On and after the effective date of the relinquishment, both of the following shall apply: (A) The portion of Route 164 relinquished under this subdivision shall cease to be a state highway. (B) The portion of Route 164 relinquished under this subdivision may not be considered for future adoption under Section 81. (4) For the portion of Route 164 that is relinquished under this subdivision, the County of Los Angeles shall maintain within its jurisdiction signs directing motorists to the continuation of Route 164. (d) (1) Notwithstanding subdivision (a), the commission may relinquish to the City of South El Monte that portion of Route 164 described in paragraph (2) of subdivision (a), pursuant to the terms of a cooperative agreement between the city and the department, upon a determination by the commission that the relinquishment is in the best interests of the state. (2) A relinquishment under this subdivision shall become effective immediately following the recordation by the county recorder of the relinquishment resolution containing the commission’s approval of the terms and conditions of the relinquishment. (3) On and after the effective date of the relinquishment, both of the following shall apply: (A) The portion of Route 164 relinquished under this subdivision shall cease to be a state highway. (B) The portion of Route 164 relinquished under this subdivision may not be considered for future adoption under Section 81. (4) For the portion of Route 164 that is relinquished under this subdivision, the City of South El Monte shall maintain within its jurisdiction signs directing motorists to the continuation of Route 164.