Drivers using Threemilestone roundabout will notice major changes at the junction with traffic lights now in place as part of work to combat congestion at the site.

With 27,000 vehicles using the roundabout each day and new homes planned nearby, engineers have made changes to the roundabout and adjacent Chyvelah Road junction to improve traffic flow.

As a result, the overall size of the roundabout has increased and traffic signals have been introduced. The mini roundabout at Chyvelah Road has been replaced with a signalised junction and the bus lane leading from the park and ride at Langarth has been extended.

The traffic lights were introduced on Wednesday evening and tested by engineers ahead of Thursday morning's rush hour. Further work will be carried out on the signals to ensure the phasing of the lights can take school term traffic flows into account.

"Our work at Threemilestone is part of the wider improvements taking place at junctions along the A390 corridor into Truro which are designed to improve traffic flow and tackle the congestion that has been a source of frustration for many," said Councillor Geoff Brown, Cornwall Council cabinet member for transport.

"We are dealing with a fixed highway network and so our engineers have looked at the pinch points and how we can improve capacity. It might seem as though installing traffic lights at these junctions would lead to more queuing, however what they actually do is help keep traffic moving.

"Once the remaining work has been completed further along the corridor, motorists will see that while their driving speeds might be slower, their journeys are smoother and less 'stop start' than before.”

The improvements made at Threemilestone roundabout are similar to those made in 2014 at Trafalgar roundabout in Truro. Statistics show a marked increase in the number of vehicles now travelling through Trafalgar roundabout - from 1,400 an hour before the work to 1,800 an hour after.

Jerry Cobb, construction manager for contractors CORMAC, said: "We would like to thank nearby residents and commuters for their patience during this complex construction. Maintaining traffic flows through this busy junction has been our priority and so, as a result, the majority of the construction has taken place at night.

"As well as the changes to the roundabout, and at Chyvelah Road, we have also installed and upgraded extensive drainage systems beneath the road and verges."

The work at Threemilestone forms part of the Truro Western Corridor scheme which will improve traffic flows and public transport links, as well as provide safe routes for cyclists and support approved developments along the corridor. Work is progressing well on the schemes at Treliske and Maiden Green, with construction on these schemes expected to be completed by early next year.