More people are using Cambridge’s guided busway, but there is disappointment as the number of journeys being made is still only “roughly half” what had originally been promised.

Cambridge’s famous busway provides an off-road link for fast buses accessing the city, and takes commuters further afield to St Ives and Huntingdon.

Figures showing there have now been “more than 23.7 million passengers since the busway opened in August 2011” have been hailed as “fantastic”. But transport campaigners say the busway is only making about 11,000 passenger journeys a day when originally it had been anticipated it would take more than 20,000.

A finance and performance report due to go before Cambridgeshire County Council’s economy and environment committee on August 16 says that in May, the busway carried 351,373 passengers. In the 12 months between May 2017 and May 2018, the report says 4.1 million trips were made.

A spokeswoman for Cambridgeshire County Council said the increase in bus users was to be welcomed, but noted it is not only passengers who benefit, as walkers and cyclists can make use of the maintenance track next to the busway.

The spokeswoman said: “It is fantastic to see all the people using it with an increase of 8.7 per cent over the last year. It is providing an effective shift away from people using their cars and encouraging people to walk and cycle along the maintenance track.

“The main reasons for building the busway were to provide people with a reliable public transport alternative to the A14 and to serve the new town at Northstowe and the new developments at Great Kneighton and Trumpington Meadows south of Cambridge.”

The spokeswoman said initial projections that the busway would make more than 20,000 passenger journeys a day are not currently being met because the busway opened later than expected. She also said numbers would have been affected by delays to the completion of Northstowe, a new town north of Cambridge whose population will undoubtedly boost busway usage.

She said: “With regards to the initial forecast figures, these were based on the busway opening in 2006 and took into account Northstowe and other housing developments being complete.”

Mr Leigh, who works with campaign group Smarter Cambridge Transport, said the 4.1 million passenger-journeys in a year amounted to about 11,233 per day.

He referenced original projections for busway use by consultant group Atkins which said that, by 2016, they would anticipate the busway would be making more than 20,000 passenger journeys a day, far more than it is currently managing.

Mr Leigh said that, even factoring in the delayed completion of Northstowe, the figures were “roughly half what they were predicted to be”.

“I think there is complacency that this is a good news story,” said Mr Leigh. “But it should be a much better news story. The forecasts, I presume, were based on good modelling and good science.”

Mr Leigh said, however, that while the number of trips is “disappointing relative to the forecast”, it was still “a beacon of success” compared with declining services elsewhere.

Former city MP Julian Huppert was the leader of the Liberal Democrats at the time the busway was going through the planning stages. He said the project had been given the go-ahead on the basis that it would take more than 20,000 passenger journeys a day.

“Clearly the busway is useful for some people,” said Dr Huppert. “But it has not delivered what was promised.”

Despite this, Andy Campbell, managing director of Stagecoach East, said the company was expecting demand to continue to rise, and said they were hoping to add more services to the busway in the coming year.

Mr Campbell said: “We’re happy with the year-on-year growth we are seeing in passenger numbers on the guided busway – despite significant delays in the development of new homes at Northstowe, and fewer-than-expected direct trains to London from Cambridge North station.

“Our own growth predictions are being met and, in line with our business case for vehicle investment, we are hoping to add more vehicles to the busway next year to meet further anticipated demand.”