Abernathy Road will be closed at Ga. 400 on weeknights and all day on the weekends for the next four to six weeks as contractors for the Transform 285/400 project begin demolition of a bridge and reconstruction of the intersection.

All closures and detours are dependent on the weather. Motorists can call 511, visit 511ga.org, or download the Georgia 511 app for the latest information.

The Georgia Department of Transportation (GDOT) and its contractor, North Perimeter Contractors (NPC), chose to follow this closure plan after the Sandy Springs City Council pushed back against a nine-day, 24/7 closure of Abernathy Road at Ga. 400.

Weather permitting, the Abernathy Road closures will begin Wednesday, Feb. 23, but might get pushed back to Thursday, a GDOT spokesperson said. Closures will be Monday through Thursday from 9 p.m. to 5 a.m., and then from 9 p.m. on Friday to 5 a.m. on Monday each week. NPC anticipates this schedule will last for four to six weeks.

By closing Abernathy Road at Ga. 400, the existing overpass bridge can be demolished and construction of a new Ga. 400 mainline bridge can begin. NPC expects the new bridge to take four to six months to construct.

A diverging diamond intersection (DDI) will be constructed for Abernathy at Ga. 400, which the GDOT spokesperson said will eliminate another traffic conflict point. Eastbound Abernathy to northbound Ga. 400 will have a free left turn lane that won’t cross traffic. The final version of the DDI will include three or four lanes in each direction, an increase from the current two lanes.

The new intersection eliminates a traffic light, reducing to two signals from Peachtree Dunwoody Road to Barfield.

Ga. 400 southbound and northbound exit ramps onto Abernathy will remain open during the detour period.

Northbound Ga. 400 traffic has been using the collector distributor lanes. Contractors expect to shift southbound traffic onto collector distributor lanes this weekend. These lanes have the same capacity as the GA. 400 mainline. As new ramps are completed, access will improve.

Once the southbound shift begins, motorists should have access to the new Hammond Drive and Abernathy Road off-ramps. Hammond Road access will be approximately one mile north of the existing exit, the GDOT spokesperson said.

Many other lane closures and detours are scheduled. Motorists on I-285 eastbound trying to reach Glenridge Drive will need to exit at Ga. 400 southbound and use the Glenridge Connector. This detour is scheduled from 9 p.m. to 5 a.m. Tuesday through Friday.

Abernathy Road closure detour directions

Northbound Ga. 400 traffic looking to head westbound on Abernathy Road still should exit at Abernathy, but turn right and head to Peachtree Dunwoody Road. After a right turn there, motorists should next turn right onto Mount Vernon Highway and make another right onto Barfield Road. That will take them to Abernathy Road where they will turn left to head westbound.

Southbound Ga. 400 traffic planning to head east on Abernathy will still take that exit, but will turn right onto Abernathy and make a left turn onto Mercedes-Benz Drive (which becomes Barfield Road). Continue until Mount Vernon Highway. After a left turn onto that road, follow it until Peachtree Dunwoody Road, where drivers will take another left and continue to access Abernathy Road.

Other detours expected

Overnight Wednesday, motorists on Roswell Road wanting to go eastbound on I-285 will need to take the westbound ramp and exit at Riverside Drive (exit 24). They will then get back on I-285 using Riverside’s eastbound entrance ramp.

The Hammond Drive southbound exit ramp is expected to close overnight on Thursday. So motorists will need to exit at Abernathy Road (exit 5) and make a left onto Mercedes-Benz Drive/Barfield Road to access Hammond Drive.

When NPC closes the Abernathy Road to southbound Ga. 400 entrance ramp – which may happen Wednesday night – Abernathy will not be closed under the mainline bridge. Motorists on Abernathy will need to take Ga. 400 north to exit 6 (Northside Drive) to get access to southbound Ga. 400.

Bob Pepalis covers Sandy Springs for Rough Draft Atlanta and Reporter Newspapers.