Cal. Sts. & High. Code § 25230

After receiving the certificate of commitment for contribution by the State, if any, and certified copies of the resolutions of approval of the boards of supervisors of all of the counties comprising the district, the board of directors of the district may proceed with final surveys, the preparation of final plans and specifications, the award of contracts and the acquisition and improvement of the highway or highways constituting the project or the unit thereof which has been approved for immediate construction.