Sometimes called ''productivity vehicles'', B-triples are about 36 metres long, 10 longer than the B-doubles now using major highways, and could be trialled on the Hume Highway next year.

The trial coincides with billions of dollars worth of wind farms planned for a renewable energy belt from Yass to Crookwell, Collector and Goulburn.

Marking the start of work on the 11.5-kilometre Majura Parkway north-east of Canberra on Tuesday, Infrastructure and Transport Minister Anthony Albanese and MP for Eden Monaro Mike Kelly made much of the increased road capacity for trucks.

Mr Kelly said the $288 million project would create a seamless artery from the southern parts of NSW to the Hume Highway, linking with a concept for developing the port at Eden on the far south coast.

''I have been in talks with several large wind farms in the area to have them import their components through the Port of Eden and the works here will see that greatly facilitated,'' he said.

Mr Kelly said the road network has to cope with the greatest capacity the government can maintain. ''The issue of getting more trucks off the roads is important, so reducing the number of trucks and having seamless carriageways like this also reduces our carbon emissions.''

He said because time is money in business, it is important to improve the flow of economic activity.

''We have to make sure [B- triples] are in tune with capacity of the system in the region and certainly there is a lot of work to be done in that respect. I note the NSW government is doing surveys on capacity, so we have to make sure we have the capacity to sustain that kind of truck movement.

''On top of that, we have 20,000 vehicles a day crossing from the Queanbeyan area into the ACT to work and the east-west traffic in that respect will be greatly facilitated and smoothed out through the overpass that will happen around the airport,'' Mr Kelly said. ''if we can also improve Pialligo Road we could achieve that bypass effect on Queanbeyan we are looking for.''

Hauling cattle and minerals from mining on the parkway will also create growing demand, and un-clogging a road artery is a huge benefit for the region, according to Mr Kelly.

Majura Valley Landcare Group founder Sherry McArdle-English said starting Majura Parkway should mark the beginning of a dream of creating a rural valley synonymous with the bush capital of Australia.

Ms McArdle-English, a truffle farmer, wants a master plan and longer leases to enable members to raise finance for their enterprises, from wine to free-range eggs.

''Let's start planning now so we don't lose this wonderful rural atmosphere,'' she said.