The Roads and Traffic Authority (RTA) agrees with residents: a suburb-sized development near Branxton will put more pressure on an already choked New England Highway.

In its submission on the Huntlee New Town proposal, the RTA said an extra two lanes in each direction would be needed for a 7000-lot development in the absence of an F3 link road.

It said that, without the road, the authority could only support a “level of development that could be sustained on the existing road network.”

Sweetwater Action Group warned a six-lane road network would be needed to serve the development in its submission to the Department of Planning, lodged in March.

The 65-page submission was on “traffic, water the environment - the whole thing.”

But a particular focus was a report by independent engineers engaged by the group. They found the current system could not cope with the scale of the development.

They suggested Wine Country Drive at Cessnock should be widened to four lanes, and the New England Highway would need six lanes.

Sweetwater Action Group spokesperson Chris Parker said Rothbury Street, which he described as a “goat track”, would also need to be upgraded as a main entry point to the site.

“It’s very interesting that the RTA should come out now,” he said.

“This is what we’ve been saying all along, and what the experts have told us.”

An RTA spokesperson conceded “there were times during peak hours on the New England Highway where the road was at capacity, including Branxton, Greta, Maitland, around Lochinvar and Rutherford.”

Its submission criticised transport suggestions raised in the plan by property development organisation LWP.

The authority said there was limited scope for rail passenger services and buses on public roads would require additional road capacity.

In its response to agency submissions, LWP said Huntlee was designed to minimise car trips through “maximising employment containment” and the provision of public transport within easy access of all residents.

The company said the concept plan was consistent with the Lower Hunter Regional Strategy and assumed the F3-to-Branxton link would go ahead.

“The RTA should therefore factor the link into its network planning,” the company said.