(b) The diversity of conditions in California is such as to require a variety of solutions to transportation problems within various areas of the state. Differences in population levels and densities, living patterns, social conditions, topography, climate, environmental circumstances, and other factors should be recognized in determining appropriate solutions to transportation problems in the various areas. Particular attention must be given to differences among the metropolitan, the less urbanized, and the more rural areas of the state. In some cases, future demands, particularly in urban corridors, may prove to be beyond the practical capabilities of a highway solution; while in other cases, environmental conditions may rule out a highway solution. In still other cases, heavy reliance upon highway transportation may prove to be satisfactory for the foreseeable future. Clearly, the appropriate mix of transportation modes throughout California to provide economical and efficient transportation service consistent with desires for mobility, will vary markedly from time to time and from area to area within the state. In all cases, regional and local expressions of transportation goals, objectives, and policies which reflect the unique characteristics and aspirations of various areas of the state shall be recognized in transportation planning tempered, however, by consideration of statewide interests.