Cal. Public Utilities Code § 130252

(a) All plans proposed for the design, construction, and implementation of public mass transit systems or projects, including exclusive public mass transit guideway systems or projects, and federal-aid and state highway projects, shall be submitted to the commission for approval. No such plan shall be approved unless it conforms to the appropriate adopted regional transportation plan pursuant to Chapter 2.5 (commencing with Section 65080) of Title 7 of the Government Code. (b) The commission shall have no approval authority over the projects, plans, and programs determined by the Department of Transportation to be necessary for the safety and maintenance of the state highway system. Such projects, plans, and programs shall be developed by the department and, to the extent feasible, be coordinated with the planning of the commission. Plans and programs involving significant rebuilding or rehabilitation of the state highway system, as determined by the department and the commission, shall be developed jointly by the department and the commission. (c) As used in this section, “plan” means a project description and not the detailed project plans, specifications, and estimates.