We're a megapolitan nation

As published in The Arizona Republic: Viewpoints by Robert E. Lang and John Stuart Hall

Predictions of growth are not new, and neither is the idea of a network of cities. However, growth and development are now altering the United States at such a scale and pace that the "mega" concept is making its way into the mainstream of urban development and public policy.

At Virginia Tech, we developed the "megapolitan" concept in 2005 to show where the next 100 million Americans might live. At Arizona State University in 2006, we studied the Sun Corridor because it is one of 20 megapolitan places.

"Megapolitan" refers to two or more metropolitan areas with anchor cities 50 to 200 miles apart. They have a high level of economic integration thanks to overlapping commute patterns and projections point out even more by 2040. The megapolitans are expected to have at least 5 million people by 2040 and be "combined statistical areas," as defined by the U.S. Census. The nation's 20 megapolitans will form 10 megaregions with roughly 10 percent of the nation's area, but 60 percent of the population.

This convergence of cities, a result of population increases, economic forces and public policies, is a familiar process. In the 1960s, Dallas and Fort Worth began merging. Now more distant cities, such as Austin and San Antonio and Phoenix and Tucson, are exhibiting the same pattern. The Sun Corridor is an increasingly connected, complex region that is projected to grow as much or more than nearly all of the other megapolitan areas.

Megapolitans vary just as states do, but they are all shaped by:

• People go where people are, concentrating economic power

Megapolitans represent a tremendous concentration of the nation's wealth and productive capacity, accounting for about 70 percent of the U.S. gross domestic product.

• Density is the best option for more people

To accommodate expected growth and have a better-built environment, policies are encouraging or mandating building up rather than out.

• New designations affect dollars and attention

Mega regions will be closely watched because of the importance of more people to federal funding formulas (such as with transportation), marketing targets and venture-capital options.

The Sun Corridor also has unique challenges. For example, how state trust land will be developed is a critical wild card since more than a quarter of the Sun Corridor is managed by the State Land Department. Large numbers of housing units have already been "entitled" by cities and towns. This is the principal step of government land-use approval, and it sets the development patterns in communities.

These are not set in stone, but jurisdictions are reluctant to change them given Prop. 207's requirements to compensate owners for negative financial impacts of land-use regulations. Tribal communities are playing an increasing role in growth and development. Leaders who think Arizona's government is too big and those who favor public investments have yet to see eye to eye.

With these complex inputs, the outcomes for the Sun Corridor are difficult to predict now. The only certainty is that to compete in the global economy and to build a more resilient and sustainable region, the Sun Corridor cannot ignore its mega challenges and opportunities.

Robert E. Lang is with the Metropolitan Institute, Virginia Tech University. John Stuart Hall is with the School of Public Affairs, Arizona State University.

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