California Code, Public Utilities Code - PUC § 161028

(a) The department shall not hold any land acquired under this division for more than 20 years from the time of acquisition.  A state or local public agency may acquire the land at any time during this period for transportation purposes.  The acquisition price to a state or local public agency shall be based upon the cost of acquisition under this division plus administrative and management costs in preserving the land.  The payment of this acquisition price shall be either monetary or in department-approved land of an equivalent value, or a combination thereof.  No land acquired under this section shall be disposed of under Section 11011.1 of the Government Code.

(b) If, at the expiration of a 20-year period, no public agency is willing or able to acquire the land, the department shall dispose of the land at fair market value without restriction on its subsequent use under this division.  All proceeds of a disposition under this subdivision shall be deposited in the State Highway Account in the State Transportation Fund.