A series of faulty traffic lights are believed to be responsible for severe congestion at a busy roundabout in Chorley.
Motorists caught queuing at the Hartwood roundabout on the A6 Preston Road described the situation as "bedlam" during morning rush hour.
Queues of around a mile long have been reported, with congested traffic stretching from B&Q in Preston Road to the Hartwood Hall pub.
The delays are being blamed on faulty traffic lights at the Hartwood roundabout, with two sets of lights appearing to be out of sync.
The problem is causing delays and congestion for motorists heading to Euxton and Buckshaw, as well as visitors to Chorley Hospital and those joining the M61.
Lancashire County Council said an engineer attended the site yesterday afternoon (June 6), but the issue does not appear to have been resolved.
Some motorists, frustrated by the chaos, could be seen turning around on the approach to the roundabout to seek alternative routes.
The problem with the traffic light sequencing was first reported to Lancashire County Council after Wednesday morning rush hour.
One motorist from Chorley said: "It was obvious there were problems from Wednesday morning (June 5).
"The sequencing has changed - it's only letting through a few cars at a time.
"If the outside lights were on green, the inner lights would be on red.
"There was just nowhere to go.
"Yesterday morning (Thursday, June 6) the queues were already horrendous at around 7.30am.
"Traffic was way back down Euxton Lane - the hospital is there as well of course. I wonder what effect that will have on ambulances, visitors and the like."
Another motorist, who asked not to be named, described the issue as "bonkers" after it reportedly took him 40 minutes to reach the roundabout from the town centre - a distance of one mile.
He said: "I rang up Lancashire County Council to report it yesterday morning.
"Traffic was building up and down the slip roads on both the northbound and southbound M61 at junction six.
"There were tailbacks from Astley Village and from the centre of town itself.
"I rang them back this morning because when we went on the website to check the reference it said 'problem solved' but it obviously isn't.
"Nothing seems to be done about it. It's becoming a big issue."
Yesterday evening (Thursday, June 6), trapped motorists could be seen queuing across the roundabout near the Hartwood, blocking traffic from leaving or entering the junction at Euxton Lane.
An exasperated motorist explained: "Lights are green and no-one can move. One driver tried to pull a U-turn when we were coming in the opposite direction on Euxton Lane near the new office blocks. It's chaos. Absolute bedlam!"
A council spokesman said: "Engineers have now fixed the problem with the signalling system at Hartwood Hall roundabout and the lights are now operating normally.
"We're sorry for any inconvenience this has caused."