Lancaster University staff and students have been particularly affected by the changes, with many being late to lectures or struggling to return home due to a lack of double decker buses to cater for the number of travellers.
Commuters also say the single deckers regularly drive past busy bus stops because they are already full.
Stagecoach say they switched their double deckers to the more frequent service which goes along the A6, with single deckers now covering Bowerham.
Sam Riches, who has commuted by bus to work at Lancaster University from the city centre for 10 years, said the new arrangements are causing a lot of difficulty.
“There are significant problems with overcrowding and people being left waiting at bus stops, especially on Route 2,” she said.
“I can see why Stagecoach wanted to put double deckers onto Route 1 (which is essentially the old Route 3), as there is heavy demand all along the A6, but the loss of capacity on Route 2, in particular caused by the switch to single deckers, is not being compensated for by the revamped timetable.
“Drivers also seem to be suffering from low morale and some are less helpful than usual – I have personally been denied access to a bus at the university underpass because it was ‘full’ even though there was clearly room for more standing passengers and even a visibly empty seat.
“Stagecoach really does need to listen to their passengers and review the impact of these changes.”
Another member of university staff, who did not wish to be named, said: “To be honest things would have been even worse without the network review – the direct double deckers have certainly helped, but with the growth in the number of people working and studying at the university, and people trying to use the bus instead of driving, it hasn’t been enough.
“Stagecoach simply don’t have enough buses to cope. We have had staff on both the 1 route through Greaves and the 2 route through Bowerham waiting over 45 minutes for a bus to work – loads of buses have been going past but they have all been full.
“We’ve also had reports of people being left behind by full buses on both routes during the middle of the day.”
Cameron Redpath, disability officer for Lancashire Young Labour, said the changes had caused “chaos”.
“It can’t go on like this, it has been absolute chaos,” he said.
“I go to Lancaster & Morecambe College and the buses just can’t cope with the demand. It should never have been changed.”
Jim Davies, chairman of Lancaster and District Bus Users Group, said a huge increase in students in the city had exacerbated the problem.
He said: “We have been working with the university and speaking to Stagecoach. As far as we can see from our research, the problem is largely to do with the number of students rather than the services changes.
“More and more students are choosing to live in the city centre which is obviously adding to the pressures.
“We do genuinely think Stagecoach are doing what they can. We know they are looking at bringing in buses from other areas to help, and we will continue to pressure them to do that.
“We have noticed in oprevious years that it’s always worse at the beginning of term.
“This year, with Greyhound Bridge’s reopening being postponed, the changes came in on the very day that the students came back so no one else had had the chance to get used to the changes first.”
Lancaster MP Cat Smith said she has asked Stagecoach to look into the problems.
“Commuters have missed lectures, appointments and connections,” she said. “I’ve asked Stagecoach to take all necessary steps to increase capacity on the 2 bus route to ease the current problem but also to update me on their long term strategy for increasing capacity on all the bus routes in Lancaster.”
A spokesman for Stagecoach said: “Our new services that were implemented on October 8 were planned to accommodate an increase in patronage in Lancaster and Morecambe, and particularly to and from the university given the anticipated growth in student numbers.
“We have increased the capacity of our most popular service that operates directly between Lancaster and the university but have seen spikes in demand greater than that anticipated at the busiest parts of the morning and evening.
“We are responding to this and are bringing in additional buses to provide even more capacity for the short periods of time in the morning and afternoon that we have seen customers having to wait longer for their bus to alleviate the problems that we have seen.
“We apologise to those customers who have had to wait longer for their bus in the last few days.”