Duplication of the Great Western Highway between Katoomba and Lithgow has been added to Infrastructure Australia's priority list - at the bottom rank of four categories.
The identification of the project as a "priority initiative" led the convenor of the Blackheath Highway Action Group, Michael Paag, to describe it as "the lowest of the lows".
"It's only going to stage two and has no business case," Mr Paag said.
"I think it shows that here we have a [state] government charging ahead with a project that can't even get high priority status.
"If it was such an urgent project of such significance, then why is it rated so low?"
Infrastructure Australia's report, released this week, ranked projects across the country in terms of their importance.
At the top is the "high priority project" followed by "priority project" and "high priority initiative". Last in ranking is "priority initiative" which is where the highway duplication is rated.
The report said "projects" were "advanced proposals that have a full business case, which Infrastructure Australia has assessed as capable of addressing a nationally significant problem or opportunity and delivering robust economic, social or environmental outcomes".
"Initiatives", on the other hand, "have the potential to address a nationally significant problem or opportunity" and need "further development and rigorous assessment".
The report said of the highway duplication plan that the "current alignment [of the highway] limits the extent to which high productivity vehicles can be used along the route".
Macquarie MP, Susan Templeman, said that "confirms what we all thought from the NSW Government's proposal to duplicate the Great Western Highway; it's all about trucks, big trucks, 'high productivity vehicles'.
"I am very concerned about the focus on heavy vehicles; it means the long B-doubles on the Great Western Highway. That won't just affect residents in the Upper Mountains, but everyone who lives in our World Heritage Area.
"While Infrastructure Australia doesn't specify how and where the duplication is to occur, it does mean the upgrade is on the national agenda.
"I will continue to work with State MP Trish Doyle, Blue Mountains Mayor Mark Greenhill and local residents to do what we can to protect the Mountains' villages and environment."
The plans for the duplication say they are designed to "carry the safest and most productive heavy vehicles, including B-doubles up to 25 metres and performance based standards vehicles up to 30 metres".
They have been widely opposed by the community.
Blackheath residents are particularly concerned at options which would push a new highway through the middle of town, swing a bypass through existing heritage homes in Station Street, or construct a wider bypass that would traverse Centennial Glen and Porters Pass, historic and very popular walking and rock climbing areas.
In Medlow Bath, which physically cannot be bypassed because of the National Park to the west and the railway line to the east, locals are alarmed at plans to widen the existing highway to accommodate the larger and longer trucks.
And Blue Mountains Council is worried that if the duplication to Katoomba went ahead, it would bring huge B-doubles through every little town, village and school zone down the Mountains to Emu Plains, all on the existing highway.
