Cal. Public Contract Code § 20381

The authority may construct the system or any part thereof, and acquire all property necessary therefor on terms and conditions that it deems advisable. The authority, without awarding a contract for the construction of the system, or any part thereof, may do the work directly and may purchase materials, hire labor, and do all other things necessary for the doing of the work. When any part of the work is to be done or performed by any public body or by the United States jointly or in conjunction with the authority, the portion of the cost thereof to be borne by the authority may be turned over to the government of the United States or to any other public body to be expended by it in the acquisition, construction or completion of the system or any part thereof. Construction contracts entered into by the authority are not subject to the State Contract Act pursuant to Chapter 11 (commencing with Section 10100) and shall be governed solely by this act, except that Chapter 3 (commencing with Section 4200) of Division 5 of Title 1 of the Government Code is hereby expressly made applicable to the system, or any part thereof, under this act. Construction contracts may be entered into in the manner and upon terms that the authority deems advisable.