The A6 Desborough Bypass is set to re-open as planned after a seven-month closure.
The road has been closed since January after a routine inspection found faults under the carriageway near the River Ise bridge.
Further inspections found faults over the railway bridge and the road has been closed since, causing diversions and misery to commuters.
But today (Wednesday) Northants Highways’ head of operations Leon Jolly said it will re-open at midnight on Sunday, September 3, meaning it will be open for commuters and parents on the school run on the Monday, and does not expect any further issues.
Mr Jolly said: “The process we’ve been using has been finding the voids and giving them structural integrity.
“I’ve not seen anything like this for 15 years, it’s rare but it does happen.
“Whilst we’ve been doing this we’ve been doing a lot of works to make sure we are not coming back here.
“I would love to make promises but we have done everything we can.”
The official diversion has sent vehicles along the A14 and A43 towards Corby, but many have ignored it and instead used roads in Desborough and Rothwell.
Mr Jolly says workers will look to carry out repairs and maintenance works to the roads affected and thanked commuters for their patience.
He said: “Every two weeks, we have looked at the diversions and the rat runs and we have a list of between eight to 10 sites that we will be carrying out small maintenance on.
“That work will take place between now and April.
“We understand the hassle that this has caused and we have done everything we can, working day and night, to get this project up and off the ground.
“We are so thankful for the support and patience from the public.”
The total cost of the whole project is unknown at this stage, but the funds have come from the county council’s budget.
The county council is in discussions with the Department for Transport to see what funding is available for the work.
Cllr Jim Hakewill (Con, Rothwell and Mawsley), said: “I am extremely relieved that, whilst at first we said it would open before after the original problem, it will now open on September 3.
“I would like to pay enormous thanks to the long-suffering residents of Rothwell and Desborough and the villages around the area, like Thorpe Underwood and Rushton.
“They have, in the most part, taken it in good humour.
“Nobody would have wanted this to happen but given it did I think the people affected will be having a few glasses of wine when it opens.”
Cllr Ian Morris, Northants County Council’s portfolio holder for environment, development and transport, said: “We really appreciate the trouble that this has caused for people and we are grateful for everyone’s patience.”