The changes come as mayors from some adjacent cities have sought changes to GDOT's plans for toll lanes on the Perimeter and Ga. 400.

Sandy Springs Mayor Rusty Paul said the announcement took him by surprise, and he wasn’t quite sure what the impact would be. If the delays mean a larger pool of contractors and cost savings, he said, that could be a good thing.

But he worried that it would be harder for commuters to navigate a number of smaller projects, and the desired impact on mobility would be lost. And he said “there are more questions than there are answers” about the changes.

“I’m not sure what the motivation is,” Paul said. “It’s hard to understand what the benefits are going to be.”

In a press release, GDOT said the changes “provide further opportunities to coordinate” with local officials and study transit options for the affected corridors.

Monday's announcement was the biggest change to date to an ambitious road-building plan unveiled by then-Gov. Nathan Deal in 2016. The 10-year plan was made possible by a gas-tax hike and other revenue increases approved by the General Assembly the previous year.

Among the projects were many benefiting metro Atlanta. They included toll lanes on the top half of the Perimeter (broken into three separate projects) and on Ga. 400, as well as new I-285 interchanges at I-20 east and west of the city. Also included was the widening of I-85 from I-985 to U.S. 129 in Jackson County in two phases.

Those projects have been progressing at various paces ever since. Under the new plan, the timeline for some projects remains unchanged. But the toll lane projects have been pushed back.

Completion of the lanes on the east side of I-285 has been pushed back from 2025 to 2028. Completion of west side lanes has been pushed back from 2026 to 2032.

The biggest section – the “top end” express lanes in the middle – was scheduled to be completed in 2028. Now it’s been split into two projects. The eastern section – from Henderson Mill Road to Ga. 400, and up Ga. 400 to the North Springs MARTA station – would be completed in 2029. The western section – from Paces Ferry Road to Ga. 400 – would be finished in 2032.

Also delayed: the Ga. 400 express lanes in Fulton and Forsyth counties. They were originally set for completion in 2024, but that’s been pushed back to 2027. GDOT said the change was made in June in response to “challenges in delivering the project on the original proposed time frame.”

GDOT does plan to do some work on I-285 sooner. That work – originally to be rolled into the larger express lane projects – will be broken out into smaller projects. They include collector-distributor lanes from Ashford Dunwoody Road to Chamblee Dunwoody Road, interchange improvements at Peachtree Industrial Boulevard and other work.

GDOT said such “bite-sized `wins’” will allow for local road improvements sooner in the construction timeline and reduce traffic congestion. And it said “adjusting the schedule of our major express lanes projects also maintains healthy competition among our bidding developers.”

Paul said one benefit of the delay could be increased communication – and planning – around transit expansion. While the state has committed $100 million to expanding transit up Ga. 400, Paul said there's no additional funding source yet. The money won't go as far as he would have hoped. And discussions about putting transit on I-285 are still in their early stages.

Meanwhile, two projects will be accelerated. The widening of I-85 to Ga. 129 will be finished by 2023, instead of 2028. And the 40 miles of truck lanes on I-75 will be finished in 2028, instead of 2029.

GDOT said the growth of freight traffic out of the Port of Savannah was a factor in the acceleration of the truck lanes. It said the first phase of the I-85 widening should be open to traffic in mid-2020, and "we want to leverage the success to advance phase 2 of that corridor's improvements."

Staff writers Arielle Kass, Ben Brasch and Greg Bluestein contributed to this report

New road plans

The Georgia Department of Transportation will delay some road construction and accelerate other projects.

Pushed back: Toll lanes on I-285 and Ga. 400.

Accelerated: Truck lanes on I-75 south of Atlanta and widening I-85 in Jackson County.