To the Board of Supervisors of Contra Costa County: The undersigned, as bidder, declares that the only persons or parties involved in this proposal. List of Requests for Qualifications and Requests for Proposals for upcoming Public Works projects.CCTA uses PlanetBids for the procurement process. Visit PlanetBids to sign up, download the RFP and other documents, and submit proposals. Each bidder must submit the following documents with its sealed bid: all Proposal pages including but not limited to federally required forms.