Cal. Sts. & Hy. Code § 73
The commission shall relinquish to any county or city any portion of any state highway within the county or city that has been deleted from the state highway system by legislative enactment, and the relinquishment shall become effective upon the first day of the next calendar or fiscal year, whichever first occurs after the effective date of the legislative enactment. It may likewise relinquish any portion of any state highway that has been superseded by relocation. Whenever the department and the county or city concerned have entered into an agreement providing therefor, or the legislative body of the county or city has adopted a resolution consenting thereto, the commission may relinquish, to that county or city, any frontage or service road or outer highway, within the territorial limits of the county or city, which has a right-of-way of at least 40 feet in width and which has been constructed as a part of a state highway project, but does not constitute a part of the main traveled roadway thereof. The commission may also relinquish, to a county or city within whose territorial limits it is located, any nonmotorized transportation facility, as defined in Section 887, constructed as part of a state highway project if the county or city, as the case may be, has entered into an agreement providing therefor or its legislative body has adopted a resolution consenting thereto.
Relinquishment shall be by resolution. A certified copy of the resolution shall be filed with the board of supervisors or the city clerk, as the case may be. A certified copy of the resolution shall also be recorded in the office of the recorder of the county where the land is located and, upon its recordation, all right, title, and interest of the state in and to that portion of any state highway shall vest in the county or city, as the case may be, and that highway or portion thereof shall thereupon constitute a county road or city street, as the case may be.
The vesting of all right, title, and interest of the state in and to portions of any state highways heretofore relinquished by the commission, in the county or city to which it was relinquished, is hereby confirmed.
Prior to relinquishing any portion of a state highway to a county or a city, except where required by legislative enactment, the department shall give 90 days' notice in writing of intention to relinquish to the board of supervisors, or the city council, as the case may be. Where the resolution of relinquishment contains a recital as to the giving of the notice, adoption of the resolution of relinquishment shall be conclusive evidence that the notice has been given.
The commission shall not relinquish to any county or city any portion of any state highway that has been superseded by relocation until the department has placed the highway, as defined in Section 23, in a state of good repair. This requirement shall not obligate the department for widening, new construction, or major reconstruction, except as the commission may direct. A state of good repair requires maintenance, as defined in Section 27, including litter removal, weed control, and tree and shrub trimming to the time of relinquishment.
Within the 90-day period, the board of supervisors or the city council may protest in writing to the commission stating the reasons therefor, including, but not limited to, objections that the highway is not in a state of good repair, or is not needed for public use and should be vacated by the commission. In the event that the commission does not comply with the requests of the protesting body, it may proceed with the relinquishment only after a public hearing given to the protesting body on 10 days' written notice.
Ca. Sts. and High. Code § 73