Highways bosses have apologised after a traffic light glitch caused rush-hour chaos in Preston.
On Wednesday evening and Thursday morning, commuters using Strand Road and surrounding streets found themselves stuck in bumper-to-bumper congestion.
With traffic lights out of sync, commuters leaving the city centre struggled to make any progress and knock-on queues backed up as far as Aqueduct Street.
On Thursday morning the problems continued, and brought many connecting roads, including the already-busy Liverpool Road in Penwortham, to a halt.
“It’s the worst I’ve ever seen it”, said one driver caught up in the jams.
“All the roads off Liverpool road are choked too as people try alternative routes.”
Speaking on Thursday evening, Ridwan Musa, highways manager for Lancashire County Council apologised for the error and inconvenience caused.
He said: “We’re sorry for the delays to people’s journeys this morning.
“The timing of the lights on a number of junctions along Strand Road went out of sync as a result of a technical problem following a software upgrade.”
Mr Musa said he hoped that the problems had now been rectified and there will be no ongoing issues.
Earlier this year, Strand Road was named as the slowest road in Lancashire in a survey by the Department for Transport, with average speeds of just 9.4 mph.
At that time, Hazel Straw, LCC transport planning manager, said traffic levels had increased and were expected to continue doing so, and one of the authority’s priorities is to secure the investment in Lancashire’s transport infrastructure.