ROCK HILL Extending Dave Lyle Boulevard east to U.S. 521 in Lancaster County has the potential to capture $23 billion in sales going to North Carolina merchants over the next 30 years, predicts a team of Winthrop University researchers.

The potential sales also would generate local sales tax – as much as $1 billion over the same time period, they said.

The study is being presented at 6:30 p.m. Thursday at Whitton Auditorium in Carroll Hall on Winthrop’s campus.

Extending Dave Lyle Boulevard from its dead end just east of the Rock Hill Galleria to U.S. 521 in northern Lancaster County is part of the region’s long-range transportation plans. The extension, estimated to cost $221 million, is unfunded. Prospects for getting state money during this year’s legislative session which started Tuesday, are unlikely, said S.C. Rep. Ralph Norman, R-Rock Hill, a key supporter of the project.

The Winthrop study looks only at the economics and demographics of the project. It does not make a recommendation on whether to build it.

Previous Dave Lyle extension studies have touted the economic development that would come with the extension, projecting dramatic increases in jobs and residences.

Winthrop’s study takes a “base-line” approach said Laura Ullrich, an economics professor and one of the study’s researchers.

The study does not assume any growth along the extension or any other demographic change in the expanded trade area, she said.

“It’s a super conservative study,” Ullrich said.

“Trade area” is defined as the area consumers do business within a 20-minute driving time.

If the extension were in place today it would add $294.68 million in retail sales potential, according to the study.

The study is based variety of sources, including economic data from 2008, 2009 and 2010, years where the economy struggled rather than boomed. That leads to conservative numbers too, Ullrich said.

One of the things that surprised Ullrich was the low percentage of people exiting Dave Lyle and traveling to the Galleria area – less than 10 percent.

The mall area is “at a disadvantage and does not reach its sales potential being disconnected to U.S. 521,” according to the study. Extending Dave Lyle Boulevard would open up the Ballantyne area and parts of Union County to retailers in Lancaster and York counties, the study says.

Assisting Ullrich with the study were Lucy Gallo and Jennifer Stanton. Both are visiting scholars at Winthrop.