5.5.1.   PURPOSE
   The purpose of this overlay is to implement policies in the ’s , the Regional Transportation Plan, and the Air Quality Plan, with specific emphasis on the . The the future arterial and needs of the community and is a tool to implement the of a safe and efficient system and the design of all serviced by that system, while assuring the economic viability of new and expanding and the continued economic stability of the community. These goals are achieved by providing for the visual improvement of designated as by implementing standards for the design and of the and , thereby providing:
   A.   A favorable visual impression of Tucson to tourists and visitors at entry points to the and on routes leading to major recreation attractions;
   B.   Enhancement of the built environment along routes of important commercial ;
   C.   Incentives for private investment and economic by providing an attractive streetscape;
   D.   Aesthetic buffering through the implementation of screening or siting of developmental elements that are incompatible with the urban character of uses;
   E.   The improvement and use of the pedestrian environment along major transit routes; and,
   F.   Some measure of air quality control by requiring with live vegetation to assist in purifying the air of carbon dioxide through oxygenation and dilution.