Cal. Streets and Highways Code - SHC § 229.35. Section 229.35.
The department shall establish and charge a fee to place and maintain generic tourist oriented directional signs in an amount at least 25 percent above its estimated cost in designing, placing, and maintaining the signs. Funds derived from the imposition of the fee shall, upon appropriation, be used to fund all operations and related administrative functions of the department pursuant to this chapter.