The Government has suggested it may stop short of rolling out road pricing across the nation, despite recently engaging the West Midlands in plans to pilot the system.
Transport Minister Stephen Ladyman told a House of Commons debate that local pilots, paid for by the Government's new Transport Innovation Fund, may reduce congestion sufficiently to mean a national scheme is not required.
The suggestion will concern West Midlands businesses, some of which have expressed opposition to road pricing, fearing it will make the region less competitive than neighbouring areas which do not operate the pay-as-you-drive system.
Dr Ladyman told the Commons: "As we conduct the pilots, we may identify the ability to solve some local problems and that may deal with the issue sufficiently well to enable us to slow down the progress towards national road pricing, or to decide that we will never need it."
Last month, the Government gave a clear signal it was keen for the West Midlands to pilot road pricing by giving it more than twice the amount of money it bid for to conduct a feasibility study on the scheme.
The £2.6 million will be spent, firstly, on six months' work looking at how radical congestion-busting measures would operate in the conurbation.
Unusually, the award also includes money towards implementation - a move viewed by many transport experts as a sweetener for the region's politicians to adopt road pricing.
Dr Ladyman said the Government predicted that congestion would be bad enough by 2015 to warrant national road pricing.
He added the caveat: "That is our current conjecture. If it proves to be wrong and we do not need a national road pricing scheme, I have no doubt that we can slow down our progress towards it."
In the summer, business leaders expressed an interest in piloting road pricing because it would allow the West Midlands a rare opportunity to shape a national scheme to its own particular needs.
Simon Murphy, chief executive of professional sector group Birmingham Forward, said: "The whole reason we were happy the seven district leaders bid for DfT money and we were happy to receive it for the feasibility study is that it will investigate ways of making the region more competitive.
"If the study shows it will have the opposite effect, then clearly we will not support it."
A spokesman for the seven West Midland district leaders, who are jointly overseeing the feasibility study, said: " Tackling congestion is a stated priority for the Government.
"Certainly everyone understands congestion is a major problem in the West Midlands that will only get worse if it's not addressed.
"The next step locally is to carry out a major congestion study, part funded by Government, that will thoroughly investigate potential solutions to the West Midlands' traffic problem."
A DfT spokesman said it would be "quite foolhardy" to rule out the possibility that road pricing would not be needed nationally in the future but the government's policy remained clear.
Since London adopted congestion charging in 2002, the DfT has been frustrated by a distinct lack of willingness to adopt similar schemes in other major UK cities.