All lanes of the I-77 ‘whirlpool’ in Statesville open just in time for holiday travel

After five years of construction, all lanes opened Thursday at the massive Interstate 77 and Interstate 40 “whirpool” interchange in Statesville, state highway officials said.  

“Right on time for holiday travel, the N.C. Department of Transportation has reached a significant milestone on the I-40/I-77 interchange project in Iredell County,” NCDOT spokesperson Jen Goodwin said in a news release. “All travel lanes in the project limits are open and in their final pattern, about 10 days ahead of schedule”.

The “whirlpool” or, as the state calls it, “partial turbine” interchange replaced a woefully outdated cloverleaf interchange built in the late 1960s. The old interchange “outlived its original purpose,” NCDOT officials said on the I-40/I-77 interchange project page.

The interchange, about 42 miles north of Charlotte, is a key component of North Carolina’s highway network because it links two of the most heavily traveled interstates crisscrossing the state.

About 70,000 drivers a day use the interchange, a number expected to leap to 110,000 a day by 2035, according to NCDOT.

The cost of the project

The $260 million project included Connecticut contractor Lane Construction Corp. widening nearly 7 1/2 miles of both interstates from four to eight lanes.

Crews also built the whirlpool interchange at I-77 and I-40 and replaced bridges over I-77 at East Broad Street and Davie Avenue.

Some work related to roads and bridges near the interchange began as far back as 2012, The Charlotte Observer reported at the time.

The project is critical to improving traffic flow “through the interchange and this region,” said Mark Stafford, the NCDOT division engineer over the project. “The original interchange was built back in the 1960s, so we need these improvements to serve drivers for years to come,” Stafford said in the release.

The cloverleaf configuration was harrowing for drivers, The Charlotte Observer reported in 2012 when work was about to begin on bridges and roads near the planned new interchange.

Westbound I-40 drivers trying to head onto I-77 South, for instance, contended with southbound I-77 drivers spilling off a ramp and onto their short exit lane.

How a whirlpool interchange works

The whirlpool interchange design spreads entrance and exit ramps much farther out than the former interchange. Vehicles from one interstate no longer spill into the lane used by others trying to access the other highway.

The design also typically eliminates left-lane exit ramps, highway officials said. Drivers use safer and longer right-lane exits and loop ramps.

Completion was delayed

NCDOT intended to complete the project in late 2022, but delays pushed completion by another year, officials told the Observer last year.

Work has taken so long because of the many nearby bridges, ramps, roads and other improvements involved in the project, officials said.

Crews completed the first half of the work in 2018, including 11 bridges, ramps, roads and other improvements.

The state widened I-40 from four to six lanes in each direction from Old Mocksville Road, just east of the I-40/I-77 interchange, to near N.C. 115 west of the interchange, according to NCDOT.

And highway workers transformed the nearby I-40/U.S. 21 interchange into a diverging diamond layout that’s also been shown to curtail bottlenecks and wrecks.

Crews completed about a dozen other projects, including reconstructing a stretch of U.S. 21, replacing or building several bridges and building several interstate ramps.

Because of the cold weather, crews will need a few more months to install the final road surface, pavement markings and markers, and rumble strips, officials said Thursday. That work is expected to last through the spring, officials said.