UPDATE: All lanes of Alcoa Highway are open to traffic again after crews finished repairing a sinkhole Thursday night.
Two of the three southbound lanes reopened around 9 p.m. Thursday, according to a TDOT spokesperson.
The lanes were closed for roughly 40 hours due to a sinkhole that formed early Wednesday morning.
PREVIOUS STORY: Southbound Alcoa Highway isn't expected to fully reopen until Thursday night, a TDOT spokesperson confirmed Thursday afternoon. Two of the three Southbound lanes remain closed following a road closure due to a sinkhole early Wednesday morning.
The northbound lanes, just north of the University of Tennessee Medical Center, reopened around 8 a.m. Thursday after a 27-hour sinkhole road closure.
Crews worked through Wednesday night into Thursday morning to repair the sinkhole on Alcoa Highway. The predicted completion of repairs was pushed back multiple times.
At 8 p.m. Thursday, a TDOT spokesperson said it was going to take longer to reopen the remaining southbound lanes, but they did still expect them to reopen sometime Thursday night.
After filling the sinkhole, crews poured cement, paving the surface and painted highway stripes on Thursday morning.
A side by side sinkhole and water main break is what led to the delays.
Both KUB and TDOT call it a 'chicken and the egg situation' – neither agency knows which one caused the other.
"We really don't know at this point in time, we haven't seen anything that points us in one direction or the other, said Jamie Davis, manager of underground construction for KUB. "What we do know is that area is prone to sinkholes. There have been a number of reported sinkholes over the years there. What we also know is that's pretty good pipe, it's well within its 100 years of life.
KUB told WBIR 10News that 30 workers spent about 400 man-hours repairing the road. They laid 40 feet of pipe, and put down 22 truckloads of rock and dirt to fill the whole.
"The depth of that pipe ultimately presented some challenges that maybe we don't face everyday," Davis said.
"The big thing is we're trying to make sure it's safe for motorists," said Mark Nagi, TDOT spokesperson. "We're not going to allow any roadway or bridge to be open if we feel it presents a danger to the motoring public."
Neither agency was able to say what the cost of repairs will be, though they say they do budget for events like this.
PREVIOUS STORY: Crews are working to repair a sinkhole that forced authorities to close Alcoa Highway and created a major traffic mess on Wednesday.
A TDOT spokesperson said once they've finished filling the hole, crews hope to begin paving.
As of Wednesday evening, all northbound lanes of Alcoa Highway, just north of the University of Tennessee Medical Center, remain closed Wednesday and southbound traffic is down to just one lane.
KUB said a broken water main ate away at the ground below the road and led to the collapse.
A few pictures from today as TDOT crews work on a large sinkhole that has developed on Alcoa Highway. All NB lanes, 2 of 3 SB lanes closed. pic.twitter.com/AFkRIe7oIK
— Mark Nagi (@MarkNagiTDOT) September 28, 2016
Luckily no one was hurt, but it left some drivers stranded and stuck in a traffic jam for hours. TDOT hopes to reopen Alcoa Highway in time for the Thursday morning commute.
Crews have been diverting northbound traffic to John Sevier Highway then onto Chapman Highway.
Only local traffic is allowed past the detour. Drivers trying to get to the UT Medical Center are able to get to the hospital in both directions. However, there are delays in the area due to the sinkhole closure.
Drivers headed north to Knoxville from Maryville are asked to take Alcoa Highway to Pellissippi Parkway to Interstate 40.
KUB crews had to finish work on the water main break before state crews started repairing the sinkhole. The water main break was about 60 feet from the sinkhole.