As the Eddington report into Britain's transport network recommends a nationwide system of road pricing, experts believe motorists should be charged for driving but disagree over how it could be implemented.
PROFESSOR DAVID BEGG, FORMER GOVERNMENT ADVISER
Price motorists off the road? That would be the case if there was a big increase in the tax burden on motorists.
That might come post-Stern with all the problems on climate change of course.
If the government wants to carry public opinion, especially motorists with them, they might try and bring it in by reducing other taxes, fuel duty and vehicle excise duty. That wouldn't go down so well with environmentalists.
If we don't do national road pricing, and we want to keep congestion constant in Britain over the next 20 years, we'd have to build five times the amount of roads the government are planning.
Hardly the kind of environmental policy we need.
EDMUND KING, RAC FOUNDATION
We believe road pricing on 10% of the network at certain times would help.
I think the problem with this is, it's an easy thing to say, it's a quite different thing to implement.
We've been talking about road pricing for 42 years, and it's always 10 or 15 years away.
What we need to do, and what the government needs to do, is show the motorist what's in it for them. And that must include some other kind of tax reduction to get people to support it.
But it must include trust, and this is one of the problems. Nine out of 10 people don't trust the government to deliver a fair system of road pricing.
SIR PATRICK BROWN, INDEPENDENT TRANSPORT COMMISSION
At least he [Sir Rod Eddington] is trying to get the government to do things which would make sense.
He says road charging is inevitable, but it will take a long time and it should start small.
It is clear we need some kind of national charging scheme, because everyone at some point drives into congested areas.
We ought to be saying the technology is available for road charging, let's get on with it. Politicians in every party are running scared.
What else can help solve the problem? Road charging is not everything.
TRANSPORT 2000, ENVIRONMENTAL TRANSPORT CAMPAIGNERS
Overall, Transport 2000 supports the Eddington message, though we remain opposed to the growth in roads and airports he supports.
We need to see action on road charging, with a clear package of measures to bring in a national scheme while investing in alternatives.
With this, government must review the roads programme - with road pricing, much of what's planned will be unnecessary or outdated.
We need a growing railway, and while we might not need a high speed line, we will need big increases in capacity to cater for increased use with road pricing and new development.
By 2050, aviation will account for 46% of UK carbon emissions, and the Eddington report makes it clear that a lot of the airport expansion supported by the government is not essential to the economy. We need a rethink.
TONY BOSWORTH, SENIOR TRANSPORT CAMPAIGNER, FRIENDS OF THE EARTH
This review sends mixed messages about the role of transport policy in tackling climate change.
We welcome Sir Rod's acknowledgment that large-scale road-building is not the answer to our transport problems, and that road-pricing and more investment in alternatives to the car are needed.
But aviation is on a collision course with UK climate targets, and airport expansion will send us in totally the wrong direction.
The government's response to this report is critical. Cutting carbon dioxide emissions must be the central theme of future transport policy.
JAMES HOOKHAM, DEPUTY CHIEF EXECUTIVE, FREIGHT TRANSPORT ASSOCIATION
Forty-five per cent of everything we spend on transport we spend on transporting goods rather than people.
Protecting freight flows along our key Trade Routes should be a priority for government that cannot wait for the introduction of road pricing or the other recommendations in the Eddington Transport Study.
PAUL SMITH, SAFE SPEED ROAD SAFETY CAMPAIGN
Threats of 'gridlock' are false. There is no long term gridlock anywhere in the world and there never will be. People will avoid travel long before they sit in gridlock. In this way congestion self-limits traffic long before gridlock.
Travel time is - and always will be - the fundamental journey choice regulator. If it takes too long to travel, then we don't travel. It really is as simple as that.
JEREMY CLARKSON, MOTORING JOURNALIST
It seems to me that we already have a perfectly fair system of road pricing which is fuel tax.
Some might say it's too high but nevertheless the system is very fair - because if you drive a very thirsty, expensive car and you drive a very great distance in it then you pay a very great deal in fuel tax.
If you have a thrifty, small car and you use it infrequently, you pay a very small amount of fuel tax.
Now that seems to me to be a reasonably fair system.