By David Wickert, The Atlanta Journal-Constitution

The reconstruction of one of metro Atlanta’s busiest highway interchanges will be finished by the end of this year. But a new era of road building has just begun.

Metro Atlanta is about to experience the kind of highway construction boom it hasn’t seen since the completion of the Perimeter in 1969. With proceeds from a 2015 gas tax increase, the Georgia Department of Transportation will spend billions of dollars over the next decade to expand the region’s highways.

The projects include an expansion of the region’s network of toll lanes, new highway interchanges and new bridges on the Perimeter. Here’s a look at the major projects under construction and on the way for these highways:

I-285/Ga. 400 interchange
I-85 widening, Phase 2
Ga. 400 toll lanes
I-285/I-20 east interchange
I-285/I-20 west interchange
I-75 commercial vehicle lanes
I-285/Peachtree Industrial Boulevard interchange
I-285 eastside bridges
I-285 westbound auxiliary lane extension
I-285 toll lanes
I-285/Ga. 400 interchange

Details: GDOT has been rebuilding the interchange connecting two of metro Atlanta’s busiest highways since 2017. The project also includes new lanes and bridges on both highways.

Cost: $800 million.

Timeline: The interchange will open to traffic by the end of the year.

What’s next: In a few weeks, GDOT will begin construction of I-285 bridges over Glenridge Drive, Ga. 400 and Peachtree Dunwoody Road. That construction will require I-285 to be reduced from five lanes to three in each direction from Roswell Road to Ashford Dunwoody Road. The reduction in lanes will continue through the end of the year. It could be a major traffic headache.

More information: https://transform285400-gdot.hub.arcgis.com/

I-85 widening, Phase 2

Details: One new lane in each direction from Ga. 53 in Braselton to just north of U.S. 129 in Jefferson.

Cost: $106 million

Timeline: Construction began in April and will finish in 2023.

What’s next: GDOT expects to begin construction on a third phase of I-85 widening — from U.S. 129 to U.S. 441 — next year.

More information:https://majormobilityga.com/projects/i85wideningphase2/

Ga. 400 toll lanes

Details: Sixteen miles of toll lanes stretching from the North Springs MARTA station to about one mile north of McFarland Parkway in Fulton and Forsyth counties.

Cost: $1.5 billion to $1.7 billion.

Timeline: Construction should begin in 2022 and finish in 2027.

What’s next: GDOT says it has received one responsive proposal from a consortium of companies that would design, finance and build the project. It’s reviewing the group’s proposal and will announce next month whether it will award the contract.

More information: https://0001757-gdot.hub.arcgis.com/

I-285/I-20 east interchange

Details: A new interchange, plus additional lanes on both highways and the replacement of various bridges.

Cost: $560 million to $650 million.

Timeline: Construction is expected to begin in 2022 and finish in 2025.

What’s next: GDOT has a short list of four groups of companies to design and build the project. It’s expected pick a group by the end of this year.

More information: https://0013915-gdot.hub.arcgis.com/

I-285/I-20 west interchange

Details: A new interchange, plus new collector-distributor and other lanes along I-20 and I-285.

Cost: $740 million to $850 million.

Timeline: Construction is expected to begin in 2023 and finish in 2026.

What’s next: GDOT will seek public comment on the project’s environmental assessment later this year.

More information: https://0013918-gdot.hub.arcgis.com/

I-75 commercial vehicle lanes

Details: Two trucks-only northbound lanes along 41 miles of I-75 from the I-475 interchange in Monroe County to Ga. 20 in Henry County.

Cost: $1.2 billion to $1.3 billion.

Timeline: Construction is expected to begin in 2024 and finish in 2027.

What’s next: GDOT expects to seek qualifications from interested firms in August and solicit public comment early next year.

More information: https://0014203-gdot.hub.arcgis.com/

I-285/Peachtree Industrial Boulevard interchange

Details: Combine the I-285 exit ramps to Peachtree Industrial Boulevard north and south and adjust the horizontal curve of the north exit ramp to reduce a bottleneck from I-285.

Cost: $16 million.

Timeline: Construction is expected to begin in the spring and finish in 2023.

What’s next: The interchange improvement is a prelude to new toll lanes on the east side of the Perimeter.

More information:https://majormobilityga.com/advancedprojects/

I-285 eastside bridges

Details: New bridges over I-285 at Covington Highway, Redwing Circle and Glenwood Road.

Cost: $47 million.

Timeline: Construction is expected to begin in January and finish in 2023.

What’s next: The new bridges are a prelude to new toll lanes on the east side of the Perimeter.

More information:https://majormobilityga.com/advancedprojects/

I-285 westbound auxiliary lane extension

Details: Add an auxiliary lane along I-285 between Roswell Road and Riverside Drive and replace the I-285/Mount Vernon Highway bridge.

Cost: $21.5 million

Timeline: Construction is expected to begin late next year and finish in 2024.

What’s next: The new lane is a prelude to new toll lanes on the east side of the Perimeter.

More information:https://majormobilityga.com/advancedprojects/

I-285 toll lanes

Details: Two new toll lanes in each direction for 40 miles along the top half of the Perimeter.

Cost: $6.1 billion to $6.9 billion.

Timeline: Up in the air. The east side lanes were expected to open in 2028, with the eastern portion of the top end set to follow in 2029 and the west side lanes and the western portion of the top end in 2032. But that timeline is in flux, and GDOT expects to release more information later this year.

What’s next: GDOT recently announced it plans to allow a private company to set and collect tolls on the Perimeter for 50 years. The firm would design, build and maintain the lanes. GDOT plans to release information about public hearings on its latest plans by the end of the year.

More information: https://majormobilityga.com/i-285-express-lanes/