In the preparation of such comprehensive plan, the planning commission shall make, or cause to be made, careful and comprehensive surveys and studies of present conditions and trends of future growth in its planning area. The plan shall be made and used for the purpose of guiding and accomplishing the coordinated, adjusted and harmonious development or redevelopment of the planning area which will, in accordance with present and future needs, best promote the public health, safety, morals, order, convenience, prosperity and general welfare, as well as efficiency and economy in the process of development or redevelopment, including adequate provision for traffic, the promotion of safety from fire or other dangers, adequate provision for light and air, the promotion of the healthful and convenient distribution of population, the promotion of good civic design, appearance and arrangement, wise and efficient expenditure of public funds and the adequate provision of public utilities and other public requirements.