TRAFFIC congestion around the Forth Road Bridge has soared since the abolition of tolls, according to new figures compiled by vehicle monitoring experts.
In the five-day period leading up to the scrapping of northbound tolls by the Government on February 11, the peak morning rush hour during weekdays extended to 61 minutes. But in the five days after the payments were abolished, it stretched to an average 91 minutes – lengthening journey times – according to surveys taken by road monitoring group Trafficmaster.
The increase occurred even though three of the days surveyed were part of the school half-term holidays in southern Scotland, when traffic is traditionally expected to be lighter.
The figures will fuel the debate over the impact of road tolls on congestion, suggesting that charges do discourage drivers from using their cars.
They also suggest that experts who told the Government last August that scrapping the tolls would worsen traffic congestion were correct.
Their advice was ignored by SNP Finance Secretary John Swinney, who said the economic benefits of removing the tolls would outweigh the disadvantages.
To get the congestion statistics, Trafficmaster cameras recorded the length of the time period at which traffic was travelling at less than 30mph at Junction 2 of the M90 to the north of the bridge.
It said the increase indicated that commuters and other travellers are now abandoning public transport and taking their vehicles into Edinburgh to take advantage of the falling cost.
"Congestion has increased since abolition of the tolls," said a spokesman. "It was thought that removing the tolls would speed up traffic but this does not seem to have been the case."
Although construction costs were paid off in 1993, the tolls since then have funded the bridge's maintenance costs.
The previous Labour-Lib Dem coalition Government rejected scrapping tolls on the grounds that their removal would increase congestion as well as lose about 20m in revenue ever year. Instead, in a plan backed by former First Minister Jack McConnell, drivers would have been able to escape paying tolls if they had more than one passenger in their vehicle.
Last month, Transport Minister Stewart Stevenson signed an order marking the end of tolls on both the Forth and Tay bridges, a move that angered Green campaign groups.
Patrick Harvie, the Green Party's transport spokesman, said: "The right approach would have been smart charges (shared car use]. As predicted, simply removing the tolls has encouraged a shift to car use and away from public transport, and the result is 50% more congestion and frustration, which damages the economy, the environment and people's health."
Evidence of the effect of removing tolls emerged after they were scrapped on the Skye Bridge in 2004. Traffic volumes rose by 50% without any significant positive impact on businesses and employment, according to the Skye Bridge Socio Economic Impact Study.
The Forth Estuary Transport Authority, which operates the bridge, said it was too early to tell what effect the removal of the tolls was having on congestion.
A Scottish Government spokesman said the removal of tolls had been widely welcomed across Scotland, and added:
"It can take some time for traffic flows to settle into new patterns and it is therefore difficult to sensibly measure any long-term changes."
Irrespective of tolls, the Forth Road Bridge still has a limited lifespan.
Investigations in 2004 found significant corrosion, resulting in a loss of strength of up to 10%. Experts agree that, if the corrosion cannot be halted, weight restrictions may have to be introduced as early as 2013.
A full dehumidification system will be in operation by late next year but it will be 18 months before engineers can determine whether the technique has been effective.
In the meantime, the Scottish Government has agreed in principle to build a new road bridge across the Forth at a cost of 4.2bn.