Route is from Route to Route in Whittier, except as follows: (

a) Route shall cease to be a state highway when Route freeway is completed from Route to Route 39. (

b) The relinquished former portions of Route within the City of Montebello, the City of Pico Rivera, and the County of Los Angeles are not state highways and are not eligible for adoption under

Section 81. For the relinquished former portions of Route 72, the Cities of Montebello and Pico Rivera and the County of Los Angeles shall maintain within their respective jurisdictions signs directing motorists to the continuation of Route 72. (

c) The commission may relinquish to the City of Whittier and the County of Los Angeles the portion of Route within their respective jurisdictional limits, upon terms and conditions the commission finds to be in the best interests of the state, if the department and the city and the county enter into an agreement providing for that relinquishment.

(1) A relinquishment under this subdivision 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.

(2) On and after the effective date of the relinquishment, all of the following shall occur: (

A) Any portion of Route relinquished pursuant to this subdivision shall cease to be a state highway. (

B) Any portion of Route relinquished pursuant to this subdivision shall be ineligible for future adoption under

Section 81. (

C) For any portion of Route relinquished pursuant to this subdivision, the City of Whittier and the County of Los Angeles shall maintain signs within their respective jurisdictional limits directing motorists to the continuation of Route 72.