We live in the first urban century. Eighty percent of the population of the United States currently lives in urban areas. Arizona is predicted to double its population by 2050 - all in metro areas.
How can Tucson sustain such growth without destroying its unique culture and environment? The answer lies in Tucson's ability to grow inward, not outward.
The city of Tucson has taken a major step in the right direction with construction of the modern streetcar and planning of quality infill development along its corridor. Other cities have done the same, including Charlotte, Denver, Portland and Albuquerque. And all have realized increased property values, tax revenue, social benefits, taxpayer savings and reduced carbon footprints as a result.
But where should such transit-oriented development be located? What should it look like?
Infill development is best located near urban centers, on perimeters of residential areas, and in vacant or underutilized land along major arterials and transit lines serving commercial and employment centers, like the University of Arizona and downtown.
While development along the modern streetcar line needs to preserve and incorporate existing neighborhood character, it does not necessarily need to look exactly the same.
Like many cities in the western U.S., Tucson has grown horizontally, not vertically. The city's skyline is dominated by one- to three-story structures. The benefits of the streetcar will not be realized by restricting development along the line to the same low-density profile. Nor does the corridor need to look like Manhattan. Taller, denser structures should be located within walking distance of the streetcar, then respectfully cascade down in height to surrounding neighborhood scale.
It's not about number of stories, but the quality of the design. Open space is top priority. Here, Tucson has the opportunity to create a unique urban form all its own.
Fear of densification is common. Too often, concern centers on a density ratios while the goal needs to be to design vibrant, comfortable places to live, work and play. Streetcars and walkable, mixed-use neighborhoods are symbiotic.
The best approach is where the city and developers engage local residents in the design process, using visualization techniques to help assess impact of proposals.
Overlay zoning is an important regulatory tool that guides infill development in a predictable fashion, while incentivizing stakeholder participation, protection of historic structures, higher densities, design review and control of appearance.
Tucson's use of the Main Gate District Urban Overlay Zone is essential to proper development of the area between West University Neighborhood, the streetcar and the university, in particular.
Strategic development will prevent scattered minidorms that cumulatively erode the integrity of core historic districts and neighborhoods not covered by the current Land Use Code.
The MGD Urban Overlay Zone Document represents best practices in transit-oriented development as demonstrated by other successful communities.
No such document can be perfect, but through the new MGD Overlay Design Review Committee process, the city, the UA and neighborhood representatives can carefully consider proposals on a case-by-case basis to help make Tucson a livable city.
Janice Cervelli, FASLA, FCELA, is dean of the College of Architecture and Landscape Architecture at the University of Arizona, a member of the Main Gate District Overlay Design Review Committee and a community director of the Downtown Tucson Partnership.