RALEIGH, NC (AP) Road construction in North Carolina has only modest effects on urban sprawl, largely following population growth rather than creating it, according to a recent study by a UNC-Charlotte researcher.
David Hartgen, a professor of transportation studies at the University of North Carolina at Charlotte, found that population growth around major urban road projects increased at rates higher than surrounding areas, but was still far less than the increased road capacity.
The study, funded by the conservative John Locke Foundation, concluded that local zoning and planning, as well as existing population density, outweighed road construction in influencing so-called sprawl.
“Within urban areas, road construction is following growth, not preceding it,” Hartgen said.
The study examines a contentious issue between road-building advocates and those who favor more investment in mass transit and urban planning designed to increase density and slow population growth to the suburbs.
Advocates of “smart growth” contend that poor planning and road construction in metropolitan areas of North Carolina is creating, rather than alleviating, traffic congestion and increasing pollution.
The Hartgen study examined growth in North Carolina during the 1990s, looking at each census tract. He looked at 312 new road-building or road-widening projects in the state and population growth within a 1-mi. corridor of those projects.
The study found that approximately 50 percent of the population growth in the state occurred outside of areas near road widening or building projects.
Population typically grew between 2 and 14 percent faster around urban road projects than in those urban areas where no new road construction took place.
That increase was far less than the increased vehicle capacity the road projects would hold, essentially equaling about the same amount of new traffic brought about by the construction of a McDonald’s restaurant, Hartgen said.
John Tallmadge, who chairs the Smart Growth Committee of the NC Sierra Club, said the findings tend to fly in the face of accepted notions that new highways are going to lead to new subdivisions.
Tallmadge pointed out that builders have been constructing new shopping centers and subdivisions in advance of the construction of the I-540 outer beltline around Raleigh, not even waiting for it to be built.
“I am sort of astonished that someone would say there is no relationship between building a new highway and development. You put a new highway in and it usually does spur development,” he said.
But John Hood, president of the Locke Foundation, said the study findings show that policy-makers should build and widen roads based on alleviating congestion and not to try to influence growth.
He said trying to slow growth, or even influence economic activity, with road construction would likely fail.
“Lots of communities expecting roads to transform their economic life are likely to be disappointed,” Hood said.