The government's senior transport adviser has sparked controversy by calling for a toll on the M8 motorway.
The proposal has prompted political opposition
David Begg said an extra lane could be built in each direction between Edinburgh and Glasgow and drivers could be charged for using them.
The chairman of the Commission for Integrated Transport believes the scheme would be similar to the M6 toll motorway at Birmingham.
There motorists are charged £2 to drive on the 27-mile stretch.
But the suggestion was branded "a nonsense" by Tory leader David
McLetchie, who said Scots motorists were already taxed enough.
In an interview with Holyrood magazine, Mr Begg said: "Some form of motorway tolling between Edinburgh and Glasgow would constrain demand.
"What you could do is put an extra lane in each direction and toll the new
"People who wanted to get to their destination quicker could do so by paying the toll.
"It is no different to the system where you have either a first or second
"We could learn from the Birmingham Northern Relief road, which does what I
have just said."
But Mr McLetchie, the MSP for Edinburgh Pentlands, said Mr Begg's suggestion was a non-starter.
He said: "It's one thing to build new roads using private capital and charge
a toll where people have an alternative - it's quite different to put tolls on
"Scotland's motorists are already the highest-taxed in Europe.
"We have got enough of a battle to stop the Edinburgh tolls in their tracks
without having to start new ones on charging people for the privilege of driving between Edinburgh and Glasgow."
The Scottish National Party's transport spokesman Kenny MacAskill also dismissed the tolls proposal.
He said: "David Begg seems to have been in London too long.
"Scotland obviously does have its own congestion problems but a
one-size-fits-all motorway tolls for everyone approach will not work.
"Additional lanes on the M8 may actually increase the volume of traffic and
increase congestion rather than constrain it, with or without a toll barrier."