California Code, Streets and Highways Code - SHC § 673

(a) Any permit issued to a permittee of the class specified in Section 678 shall contain a provision that in the event the future improvement of the highway necessitates the relocation or removal of the encroachment the permittee will relocate or remove the same at the permittee's sole expense. In that event, the department shall serve on the permittee its written demand specifying the place of relocation, or that the encroachment is to be removed from the highway, and specifying a reasonable time within which the work of relocation is to be commenced. The permittee shall commence the relocation or removal within the time specified in that demand and thereafter diligently prosecute until completion.

(b) All permits, other than those issued to permittees of the class specified in Section 678 or the class specified in Section 680, are revocable on five days' notice and the encroachment shall be removed or relocated as may be specified by the department in the notice revoking the permit and within the time specified by the department, which time shall not be less than five days, unless the permit so provides.

(c) The department may waive the requirement of subdivision (a) that the permittee bear the sole expense of relocating or removing an encroachment, if the encroachment consists of a track or roadway that serves as an exclusive public mass transit guideway owned, operated, and maintained by a publicly owned mass transit authority.