The Triangle is in a building boom for roads. Get ready to navigate more orange barrels.

A change in the way the state allocates money for road projects is helping fuel a highway building boom in the Triangle.

The N.C. Department of Transportation has more than $6 billion in major highway projects underway or in the works in Wake, Durham, Orange and Johnston counties. They include the $2.2 billion extension of the Triangle Expressway across southern Wake County, but also more than two dozen efforts to widen highways or turn roads into freeways that will have Triangle drivers squeezing between Jersey barriers and orange construction barrels for years to come.

These don’t include dozens of smaller state and local efforts to add lanes or improve congested intersections in the coming years. Nor does it include three major transit projects that are meant to provide alternatives to driving: the Durham-Orange light rail line, a bus rapid transit system in Raleigh and a commuter rail line stretching from Garner to Durham.

“It’s as busy or busier than I’ve seen in my more than 20 years here,” said Joey Hopkins, the chief engineer for the NCDOT division that includes Wake and Durham counties.

Hopkins said the volume of work in the Triangle outstrips an earlier busy patch in the late 1990s, when the state planned and began building the Knightdale Bypass and the northern arc of I-540 and widening I-40 and I-85 in Durham.

There’s no single explanation for the flurry of activity, Hopkins said, but the Strategic Transportation Investments law proposed by former Gov. Pat McCrory and approved by the General Assembly in 2013 is a big factor.

The law was meant to remove politics from the decisions about where to build or widen highways and established data-driven formulas for determining where roads were needed most. It replaced a system put in place in 1989 that was referred to as the “equity formula,” because it spread highway money across the state “like peanut butter,” said Eric Lamb, the transportation planning director for the City of Raleigh.

The new formulas meant more money went to growing urban areas where traffic congestion is worst, Lamb told an audience in Raleigh in late November.

“It really wasn’t a surprise to us that five of the top 10 projects in North Carolina were in Wake County,” he said, referring to the first time the formulas were applied.

After years of planning, those big projects are getting built, Hopkins said.

“We’re starting to see the fruits of that a few years after the law passed, because it takes time to get the projects developed,” he said.

NCDOT has also tried to pick up the pace of development to finish more projects on time and to pay down the fund for construction and maintenance. The fund had ballooned to $2.3 billion at its peak in March 2017, said NCDOT spokesman Steve Abbott. As of Dec. 1, it was down to just under $500 million.

The rush of work comes as NCDOT struggles with an aging workforce and shortage of employees. Bobby Lewis, the agency’s chief engineer, told a Board of Transportation committee this fall that nearly one in five jobs in the department is vacant and that 45 percent of employees are age 50 or older. About 2,000 will be eligible to retire in the next five years.

But Hopkins notes that NCDOT is better able to weather the labor shortage now because it relies on contractors for much of the planning and design work that was once done by state employees in Raleigh.

“We’re not slowing down,” he said. “If we don’t have the people do it in-house, we’re looking to go out to contract with it.”

Here are 10 of the major road construction projects either underway or planned in the Triangle. The cost figures come from the latest State Transportation Improvement Program list from December 2018.

Extend the 540 Triangle Expressway from N.C. 55 in Holly Springs 28.4 miles across southern Wake County to U.S. 64 near Knightdale. NCDOT has awarded a $314.5 million contract to build the first 8.6-mile leg, from U.S. 401 to I-40, and expects work to begin next summer. But it still needs environmental permits, which four groups led by the Southern Environmental Law Center have opposed. Total cost: $2.2 billion.

Widen I-40 from I-440 in Raleigh to N.C. 42 in Johnston County and reconfigure the interchange at N.C. 42. Construction got underway this fall and is expected to be completed in 2022. Total cost: $463.3 million.

Widen the Beltline between Wade Avenue in Raleigh and Walnut Street in Cary, including new interchanges at Wade Avenue, Hillsborough Street, Western Boulevard and Jones Franklin Road. The project also includes building a new underpass to carry Blue Ridge Road under Hillsborough Street and the N.C. Railroad tracks near the N.C. State Fairgrounds. Construction begins in 2019 and will take four years to complete. Total cost: $478 million.

East End Connector, the 3.9-mile highway that will connect the Durham Freeway with I-85 on the east side of Durham when it opens in late 2019. Total cost: $211.2 million.

Widen I-40 from U.S. 15/501 to I-85 in Orange County. The $161 million project will eliminate one of the last four-lane stretches of I-40 in the Triangle, though construction isn’t scheduled to get started until 2023.

Reconstruct the I-440 interchange at Glenwood Avenue and other changes to Glenwood and Blue Ridge Road. Construction was expected to get started in 2019, but NCDOT extended the design process at the urging of residents along Ridge Road who worry about the project’s impact on their neighborhoods. Then the department decided it didn’t have the money on hand to start the project until 2025. Total cost: $231.3 million.

Convert U.S. 1/Capital Boulevard to a freeway, from I-540 to N.C. 98. Construction is scheduled to begin in 2021. Total cost: $464 million.

Overhaul and widen N.C. 54 from U.S. 15/501 to N.C. 55 in Chapel Hill and Durham. Construction is scheduled to begin in 2024. Total cost: $295 million.

Turn U.S. 70 into a freeway from I-540 to T.W. Alexander Drive in Raleigh, including a new interchange at Brier Creek Parkway. Construction is scheduled to begin in 2021. Total cost: $95.4 million.

Turn U.S. 70 into a freeway from T.W. Alexander in Raleigh to Lynn Road in Durham. Construction is expected to begin in 2024. Total cost: $206 million.

Reconstruct the I-40 interchange at I-440/U.S. 1 near the Crossroads area of Cary. Construction is scheduled to begin in 2022. Total cost: $151.8 million.

Reconstruct U.S. 64 between U.S. 1 in Cary and N.C. 55 in Apex. Construction is scheduled to begin in 2022. Total cost: $112.8 million.

Related stories from Raleigh News & Observer

Richard Stradling covers transportation for The News & Observer. Planes, trains and automobiles, plus ferries, bicycles, scooters and just plain walking. Also, #census2020. He’s been a reporter or editor for 32 years, including the last 20 at The N&O. 919-829-4739, rstradling@newsobserver.com.