The regional planning commission shall have the function and duty of making and adopting a comprehensive plan for the development of the region. The comprehensive plan, with the accompanying maps, plats, charts, programs and descriptive and explanatory matter, shall show the commission’s recommendations for such development and may include, among other things, without limitation because of enumeration, the general location, character and extent of main traffic arteries, bridges and viaducts; public places and areas; parks, parkways; recreational areas; sites for public buildings and structures; airports; waterways; routes for public transit; and the general location and extent of main and interceptor sewers, water conduits and other public utilities whether privately or publicly owned; areas for industrial, commercial, residential, agricultural or recreational development. The comprehensive plan shall be made with the general purpose of guiding and accomplishing a coordinated, adjusted and harmonious development of the region which will, in accordance with existing and future needs, best promote public health, safety, morals, order, convenience, prosperity or the general welfare, as well as efficiency and economy in the process of development.