Motorists face up to five more months of roadworks after delays caused by heavy rain.
Work to widen and make improvements to the A45 Wilby Way roundabout near Wellingborough started in September last year and was due to take 21 weeks.
But the improvements, which involve widening the A45 eastbound entry and exit at Wilby Way roundabout and the A509 entry and exit, may now not be finished until June due to the recent wet weather.
A spokesman for the Highways Agency said: “We are doing everything we can to complete the A45 Wilby Way pinch point scheme as soon as possible.
“However, workers have been severely hampered by the weather and huge amounts of rain.
“There has also been an issue with a high voltage electricity cable, which needs to be relocated and involves discussion with the supplier Western Power.
“We understand the importance of this scheme to the local area and economy, but some issues are beyond our control and I’m sure everyone will understand safety has to come first, especially when dealing with high voltage cables.
“At this stage, we hope to complete the work by June.”
Other improvements being made are to the road surface, drainage, signs, signals and street lighting.
The pinch point improvement programme for the strategic road network in England is part of the Government’s growth initiative.
It aims to provide small improvements which can make a big difference by easing congestion and making journey times more reliable for drivers.