California Code, Streets and Highways Code - SHC § 162

(a) Unless the commission finds that it would be impractical, any state highway exclusive and preferential lane for buses and other high occupancy vehicles constructed on new alignment or new structures shall be designed and constructed on horizontal and vertical alignments, including the grade, curvature, and horizontal and vertical clearances, so that the lane may readily be reconstructed as an exclusive public mass transit guideway, using the department's rail transit design criteria.

(b) Notwithstanding subdivision (a), prior to designing a state highway in conformance with this section, the department shall consider all of the following: