Cal. Gov't Code § 66510

The regional transportation plan shall include, but not be limited to, the following segments of the regional transportation system:

(a) The national system of interstate and defense highways, the California freeway and expressway system, and other highways within the state highway system.
(b) The transbay bridges.
(c) Mass transit systems.
The commission shall pay particular attention to the interfacing of the various modes of transportation.