The report is looking at the environmental impact

Transport expert Professor Phil Goodwin is expected to take several weeks to write a report on plans to widen the road between junctions 11 and 19.

Birmingham Chamber of Commerce said economic growth and transport are linked and time was being wasted.

Campaigners opposed to the scheme claim it would damage the environment.

If this country's to keep up.. we've got to fix the infrastructure Jerry Blackett, Birmingham Chamber of Commerce

Under the plans an extra lane would exist from junction 11 at Cannock, Staffs, to junction 19 at Knutsford.

The Group Against Motorway Expansion (GAME) said environmental issues are the most important thing.

Spokesman John Gale said: "They have this ridiculous attitude of saying 'let's not bother to look at the evidence - let's just get on and blow 2.9bn'.

"They don't seem to appreciate what is happening to the environment, what damage we are doing.

"If they're that worried about the economic costs, then they should find something else that does not require this massive transportation."

Road network

Jerry Blackett, from Birmingham Chamber of Commerce, said: "Do you know it took us 22 years to build the toll road, three years to build it because we spent 19 years talking about it?

"If this country's to keep up with China, India and the economies that are booming, we've got to fix the infrastructure.

"We've got to fix transport."

Prof Goodwin's report will look at how widening would affect the amount of traffic and the impact on the local road network when cars come off the motorway.

He will also examine the environmental impact, including landscaping and noise.