Work to reduce congestion on the A1 at the Black Cat roundabout near St Neots has been delayed.
The £5.6million scheme began at the end of June and was due to be finished this month.
But extra work and poor weather has put the schedule back and it will now be delivered by the end of March.
Once complete, there will be a new road layout with a larger and wider roundabout, new safety fencing, improved drainage, new surfacing on the roundabout and new street lights. Traffic lights are also set to be introduced.
Highways Agency’s project manager for the scheme, Mark Saunders, said: “The improvements will finish later than anticipated because of the weather and additional works which we didn’t anticipate.
“We found the road was in a worse state of repair than originally thought, so we have had to plane out more to compensate.
“We apologise for the delay and I’d like to thank drivers for their patience while these works continue.”
The scheme has been designed to ease congestion at the roundabout and to improve safety. It is part of the Government’s £317million pinch point programme, which aims to boost local economies by reducing congestion and delays at key locations.