The long awaited Broughton bypass has been delayed by a further five months and is expected to cost an extra £3m.
Due to have been completed by March 2017, the scheduled completion date for the bypass is now August next year.
Lancashire County Council says delays in construction have been caused by complications related to ground conditions, which LCC Director of Development and Corporate Services Eddie Sutton described as “more challenging than had been indicated by the initial survey”.
He said this had impacted on the work on Brooklands Bridge at the southern end of the scheme, which will now require signifantly deeper foundations.
Along with other costs, LCC says this will lead the original cost of £24m to increase by up to £3m.
Mr Sutton revealed a different bridge foundation had been designed that would have enabled completion of the bypass on time and on budget, however this had been rejected by the Environment Agency.
The extra funding needed will come from the Preston, South Ribble and Lancashire City Deal, which aims to cater for the growing population by creating more than 20,000 new private sector jobs and constructing 17,000 new homes.
Mr Sutton expressed his thanks to residents of Broughton for their patience during the lengthy development.
Drainage and earthwork will start on the east side of the A6 to divert traffic while the roundabout is constructed.