Work to supply gas to a developing housing estate in Northampton will be finished by the end of Wednesday, engineers have said.
A four-way traffic light system has been operating at the Boughton roundabout, on the A508, since last Tuesday.
Express Pipelines originally said the job would be finished on Saturday, January 9, but they have been unable to keep to the timetable.
A new deadline of the end of Wednesday has now been set.
A supervisor, who declined to give his name, said: “You don’t know what you’re going to encounter until you put your shovel in the road.
“It has turned out that it’s a road laid on top of another road and therefore it’s taken us longer than we hoped.
“We realise it’s upset a lot of people in Northampton and I apologise for that. Our guys have been working extra hours to get it finished as soon as we can.
“Worst case scenario is that we will be done by the end of Wednesday.”
The workmen are connecting a gas main to the Buckton Fields estate to supply homes that are currently being built there.
House builders Bloor Homes engaged Gas Transportation Company Ltd to carry out the work, who then subcontracted Express Pipelines.
Motorists north of Northampton have been caught in long queues caused by the temporary traffic lights for a week now.
It led to the lights being operated manually from last Wednesday, in order to respond to build-up from a particular direction.