Raleigh, N.C. — Construction crews could break ground on two remaining segments of the Interstate 540/N.C. Highway 540 loop in Wake County by as early as 2014.

Steve Dewitt, the chief engineer for the North Carolina Turnpike Authority, said Thursday that preliminary plans have the southern segment stretching 18 miles from N.C. Highway 55 near Holly Springs to the Interstate 40 Clayton Bypass.

The eastern portion would run 12 miles from the I-40 Clayton Bypass to the existing I-540 near Knightdale.

Completing the loop would mean the roadway would connect communities in the southern half of the county, including Apex, Holly Springs, Garner and Clayton.

Environmental studies are still needed, Dewitt said, and other details still need to be worked out. Funding would come from tolls.

"In the five-year time frame, it's reasonable to expect this project can move forward, in terms of construction," he said.

Right now, I-540/N.C. 540 runs from N.C. 55 in Cary to U.S. Highway 264 in eastern Wake County.

Construction started this year to complete a 16-mile stretch of N.C. 540 that will run from Morrisville to N.C. 55 in Holly Springs.

That's expected to be complete by 2012 and will be part of the state's first toll road.