The prevailing wage law generally requires a contractor or subcontractor on a public works project to pay its workers the prevailing rate of wages as "set by the DIR Director for each locality where the work is to be performed for each craft, classification or type of worker needed to execute a public works contract, based on a statutorily mandated methodology." (Sheet Metal Workers Internat. Assn., Local Union No. 104 v. Rea (2007) 153 Cal.App.4th 1071, 1078 63 Cal. Rptr. 3d 672 (Sheet Metal Workers);See 1770.) It was enacted to protect and benefit employees of contractors who work on projects paid for with public funds. (Lusardi Construction Co. v. Aubry (1992) 1 Cal.4th 976, 985.) In setting the prevailing wage rates, Labor Code section 1773 requires the Director to consider applicable wages established by collective bargaining agreements and federal public works projects in the locality. If those are not actually the prevailing rates in the area, the Director must "obtain and consider further data from the labor organizations and employers or employer associations ... ." ( 1773.) Labor Code Section 1773.2 requires a body awarding a public works contract to specify in its call for bids the prevailing rate for each craft, classification or type of worker needed to execute the contract, or to include a statement that copies of the prevailing rates are on file at its principal office for review. In the bid notice for the Bay Bridge contract, Caltrans stated that the prevailing wage information was available in the labor compliance office at the offices of the Caltrans district director, and also available on the Department of Industrial Relations Internet Web site. "Prevailing rates and related scope of work provisions for the affected craft, classification or type of worker are regularly posted on the DIR's Web site by its Division of Labor Statistics and Research (DLSR)." (Sheet Metal Workers, supra, 153 Cal.App.4th at p. 1075.) Labor Code Section 1773.4 provides that within 20 days of a call for bids, any prospective bidder or representative of any craft, classification or type of worker involved may petition the Director "to review the determination of any prevailing wage rate or rates upon the ground that they have not been determined in accordance with the provision of Section 1773 of this code." Implementing regulations require that a petition seeking review under section 1773.4 state, inter alia, "the manner in which the wage rate determined by the Director fails to comply with the provisions of ... Section 1773." (Cal. Code Regs., tit. 8, 16302, subd. (c)(7).) Judicial review of the Director's prevailing wage determinations is barred unless the administrative procedures specified in section 1773.4 have been exhausted. (Sheet Metal Workers, supra, 153 Cal.App.4th at pp. 1082-1083.)