Streets and Highways Code § 193
ARTICLE 5. Funds for Highway and Public Mass Transit Guideway Purposes
The State Highway Account money allocated and available each year for state highways shall be expended by the department:
(a) On the locations determined by the commission, to acquire the necessary real property or interests therein for, and to construct or improve to standards justified by traffic requirements, the state highways in the state highway system.
(b) To construct or improve highways in state parks in the manner provided by law.