California Code, Public Utilities Code - PUC § 161004

(a) Designated by the commission as necessary under the adopted state transportation improvement plan.

(b) Designated by a transportation planning agency, county transportation commission, or the San Diego County Metropolitan Transit Development Board as necessary under the adopted regional transportation implementation plan.

(c) Within the adopted route of a state highway.

(d) Within the adopted route of a county or city highway or exclusive mass transit guideway which is consistent with the county or city general plan.

(e) Designated by the commission as being within one of two or more proposed routes or alignments for a state highway.