N&O: Will This be the Triangle's Biggest Highway Interchange?
From the News & Observer...
“Completing the final sections of the 540 loop road around Raleigh will mean building what could be the largest and most complicated highway interchange in the Triangle.
N.C. 540, the Triangle Expressway, will meet Interstate 40 south of Garner at the spot where the U.S. 70 Bypass now splits off heading east into Johnston County. That will create a confluence of three interstate-grade highways at an interchange that will cover some 650 acres, an area equivalent to four-fifths of Raleigh’s Dix Park.
To make the design more challenging, the Triangle Expressway is a toll road, and N.C. Department of Transportation engineers have included separate exit ramps from I-40 to make sure drivers don’t accidentally get on it.
The design they came up with looks like nothing in the Triangle now. It’s dominated by a large exit and entrance ramp connecting I-40 and N.C. 540 that will circle where the five legs of the highways meet. A rendering of the interchange elicited a wave of murmurs when it was flashed on the big screen at a public hearing at Wake Tech Community College last month.
The interchange is a custom design, chosen from several versions that NCDOT engineers sketched out. They could not simply copy one from elsewhere, because they needed to work with the I-40/U.S. 70 interchange that is already there, said Roy Bruce, the senior project manager for the project, which NCDOT calls Complete 540.
Bruce said it makes sense for the Triangle Expressway to cross I-40 at this spot, so that traffic to and from Eastern North Carolina can move seamlessly between N.C. 540 and U.S. 70.
”It gives us continuity,” he said.
There will be some tight loop ramps, including the existing one from westbound U.S. 70 onto eastbound I-40. But many of the other ramps, including the big circular one, are large enough that drivers can go 55 mph from one highway to the next.
N.C. 540 will come over the top of the two existing roads, so at some points there will be three levels of highway. But with I-40 already depressed here, and the large circular ramp system to spread things out, there will be no soaring ramps like those seen in urban areas such as Los Angeles or suburban Washington, D.C. At its highest point, N.C. 540 will be 45 feet above I-40, Bruce said. ...”