The prototype of smart growth has been Portland, Ore. There, politicians and planners literally have drawn a line in the dirt, refusing to let growth spread beyond an arbitrary urban growth boundary.

But a new study released this week by the Georgia Public Policy Foundation shatters myths about smart growth by examining the consequences. In comparing Atlanta -- the presumed poster child for "sprawl" -- with Portland, dramatic differences emerge in the quality of life that results from the two approaches to growth management.

Authored by Wendell Cox, a noted transportation planner and public planning consultant, "American Dream Boundaries: Urban Containment and its Consequences" is a lesson for Atlanta and other major metropolitan areas on what not to do when it comes to regulating growth and development. More importantly, it dispels some of the myths generated by academicians, public planners and politicians.

Among the fallacies of smart growth, according to the Cox report:

Portland's smart growth strategy that devalues roads and emphasizes that transit eases congestion.

Not if you look at the numbers, writes Cox. Among urban areas with more than 1 million residents, Portland experienced the largest per capita increase in daily vehicle miles traveled from 1990 to 1999.

During the same time period, Atlanta's per capita daily VMT increased 20.6 percent compared with 28.5 percent in Portland. Portland's traffic will get worse, thanks to its transit-oriented transportation plan, which will increase the daily hours of delay on roadways by 600 percent by 2020.

Smart growth makes housing more affordable.

Portland's housing prices have escalated well ahead of Atlanta and the nation. The median price between 1991 and 2000 in Portland rose 110 percent to $168,000; Atlanta's rose 65 percent to $150,000 and nationwide the average rose 49 percent to $152,000. Homeownership has dropped 6.6 percent in Portland from 1990 to 2000. Home ownership in Atlanta is up 11 percent.

"If Atlanta had experienced the same loss in home ownership during the 1990s as Portland, 240,000 households who currently own their home would be renters instead," the report states. If Portland trends occurred in Atlanta, 25,000 fewer African-Americans and 3,400 fewer Hispanics would own homes.

Smart growth produces a stronger city, planners argue.

Not quite, Cox's research counters.

The best evidence of this is in jobs and household income. During the 1990s, Atlanta's employment increased 37.3 percent compared with 30.5 percent in Portland. And median household income also increased more dramatically in Atlanta, up 52 percent here from 1990 to 2000 compared with 44.7 percent in Portland. As metro Atlanta "sprawled," its economy flourished.

Smart growth policies promote more efficiency in government, particularly when it comes to infrastructure costs.

Advocates of smart growth have argued that government works more efficiently and costs less if contained in a smaller area, such as Portland's urban growth boundary. But the opposite is true if you compare Portland and Atlanta. State and local government spending per capita was almost double in Oregon compared with Georgia during the 1990s. State and local government costs rose 13 percent per capita in Georgia compared with 82 percent in Oregon.

Smart growth policies actually require more government spending. "Newer suburban areas are more open to innovative stategies such as competitive contracting and privatization, which significantly lowers infrastructure costs," Cox wrote.

The Georgia Regional Transportation Authority is set to enact its first land-use restrictions this summer. Before proceeding it should examine this new study. Sure, Cox waves red flags. But the proper response is not to dismiss the critics, such as Cox, but to address the legitimate issues they raise.