TO misquote Field of Dreams, the 1989 baseball drama starring Kevin Costner, if you build it, they will come.

Transport chiefs have been accused of hampering efforts to reduce congestion and cut climate emissions after a rise in traffic following the construction of the £1.35 billion Queensferry Crossing.

HeraldScotland: Camley's Cartoon: More cars using Queensferry Crossing.Camley's Cartoon: More cars using Queensferry Crossing.

Officials at Transport Scotland had claimed any new traffic growth across the Forth would be carried by public transport and not by new car journeys.

But statistics show more than one million extra journeys – 27.3 million in total – had been made over the Queensferry Crossing in the 12 months to October 2019.

This is a rise of 3.9 per cent on the same period the previous year.

Alison Irvine, director of transport strategy and analysis for Transport Scotland, admitted the rise in traffic was “not the direction of travel that we would want to see”.

Scottish Greens transport spokesman John Finnie said the evidence made clear the new bridge, which was opened in 2017, has not resolved congestion issues into Edinburgh.

He added: “Why would it? We’ve known since the 1960s that building more roads increases traffic.

“The growth in traffic is just not sustainable and it is clearly impacting on communities. The Scottish Government must listen to the experts. Bus lanes and road allocation isn’t going to solve the issue on its own.

“In a climate emergency there needs to be regular, reliable and integrated public transport, so that it becomes the easiest option. That’s why the Scottish Greens propose public ownership and phasing in free bus travel.”

Earlier, Mr Finnie quizzed Ms Irvine at Holyrood’s Rural Economy and Connectivity Committee.

He said: “This committee, and indeed the predecessor committee, have maintained a very keen interest in what’s a significant project.

“Throughout that period, Transport Scotland have followed a consistent line and that line is, I quote here: ‘Any increase in demand to cross the Forth was to be met by public transport.’

“Now, that’s not happened and there’s a million more car journeys, so what’s going wrong with that headline approach that you were taking?”

Ms Irvine said the Queensferry Crossing “does not have any additional capacity in comparison with the Forth Bridge”, as both have two lanes in each direction.

She added: “However, what we have is a more reliable and resilient crossing which has obviously helped improve the efficiency of that corridor.

“As you’ve set out, the project was a replacement for traffic as set out in the Forth Crossing Act and we’ve always had that focus on promoting public transport across the corridor.

“This is in line with the ambitions set out in the new national transport strategy which obviously emphasises the need to reduce the need to travel unsustainably in order to meet our objectives on climate change.”

She continued: “Very early findings at this stage of the One Year After project indicate that we’re already making progress towards the transport planning objectives that we’ve set and we’re seeing early signs that the public transport strategy is encouraging more people to travel by sustainable modes.

“We don’t yet have even two full calendar years of the full motorway operation, so it’s important that we don’t leap to conclusions about the rate of traffic growth.

“But obviously the data mentioned…is correct, and it’s not the direction that we would want the travel to go in.”

Ms Irvine later added: “The information that we have just now, while I will admit is not the direction of travel that we would want to see, is still less than was forecast.”

She said nine of the 19 planned “interventions” to improve public transport over the Forth had been delivered, while journey times had improved.

But Mr Finnie said an increase in traffic of potentially more than one million, as forecast, was "certainly not going to help the climate targets".

Douglas Robertson, managing director at Stagecoach East Scotland, said the new crossing had led to a growth in bus passenger numbers, which is accelerating over time.

However, Ewan Kennedy, transport and planning manager at Edinburgh Council, said “north of” 60,000 cars commute into Scotland’s capital every morning. He said congestion had created “a huge issue” for communities along the A90 route.

SNP MSP Stewart Stevenson suggested the traffic increase could be down to the Queensferry Crossing’s resilience to bad weather which would have led to closures on the old bridge.

His party colleague Maureen Watt also pointed to increases in housebuilding.