California Code, Government Code - GOV § 14031.1

In accordance with federal regulation (49 C.F.R. 661.21), the state or a local agency, relative to the use of federal funds for transit purposes, shall be authorized to provide a bidding preference to a bidder if the bidder exceeds Buy America requirements applicable to federally funded transit projects.  The state and each local agency shall have the discretion to apply those preferences.  The Department of General Services shall have the sole authority to establish policies and procedures for use of this section by state agencies, as defined in Section 11000.