It is hereby declared to be the policy of the State of California to develop transit system districts in the various metropolitan areas within the state for the benefit of the people. A necessity exists within San Diego County for such a system. Because there is no general law under which this district could perform this distinct function, only a specially created district can operate effectively in the San Diego metropolitan area. Because of the unique problem presented by that metropolitan area, the adoption of a special act and the creation of a special district is required.