The mayor is leading the opposition to plans to duplicate the highway from Katoomba to Lithgow.
Cr Mark Greenhill said it would allow trucks up to 30 metres long to travel to and from the Central West. And they would all have to join the existing highway at Katoomba.
"This looks to me like a recipe to dump more and bigger trucks on to the Great Western Highway, impacting every town from Lapstone to Katoomba."
The plans specify the road will carry B-doubles up to 25 metres and performance based standards vehicles up to 30 metres.
The minister for regional transport and roads, Paul Toole, unveiled the plans in Lithgow last Thursday.
He said the project posed particular difficulties with the topography, rail line, location of villages and the World Heritage Area, which will not be touched.
But he said it was "crucial for better connections to the Central West and improving productivity".
The plans would see a new road built from the Explorers Tree to Medlow Bath on the western escarpment.
Medlow cannot be bypassed because of the terrain. Instead, it would be widened and a 60 km/h zone imposed.
A major sticking point is Blackheath, where no decision has yet been made. Options are:
- Duplicating the highway through the centre of town, requiring acquisition of home and businesses;
- An outer bypass with bridges over Shipley Road, Centennial Pass and Porters Pass;
- A bypass next to the railway line with impacts on residential and commercial; or
- Tunnels under the railway and the Christian College with ventilation stacks.
A tunnel would go from Mt Victoria to the bottom of Victoria Pass.
The Blackheath Highway Action Group called it a "gigantic waste of taxpayers' money".
Spokesman Michael Paag said: "The numbers don't stack up, the experts don't support it ... and it won't solve the transport needs of the Central West.
"But it will forever damage the Blue Mountains and leave a legacy of frustration and missed opportunity."
Blue Mountains MP, Trish Doyle, said:
"This announcement is a sop to Nationals voters in Bathurst and Dubbo who have been force-fed like French ducks this lie that their quality of life and economic fortunes will be radically improved once the Coalition Government is permitted to clear fell the Blue Mountains and build a motorway to the Central West."
Details about how to comment and information sessions on the RMS website.