A planning application for the project, which will see a four-mile bypass, running from the Ellesmere Road Roundabout at Battlefield, in the north of the town, to the A5 at Churncote Island, is expected to be submitted by Shropshire Council this month.
Concerns have been raised over the cost, environmental impact and potential effectiveness at getting cars out of the town centre, and campaign group Better Transport Shrewsbury has said it will be studying the application closely.
A spokesperson said: “This is a key point in the chequered history of this controversial project and we will be going through the documents with a tooth comb. We have been keen to get answers to many questions for a long time and have been told they will be covered in the planning application.
"One major issue is the fact we are in the middle of a worsening climate emergency. The council have spent a year preparing a carbon reduction strategy, to get to net zero emissions, but our preliminary calculations suggest the extra CO2 from construction of the road could exceed the total emissions from all the council’s other activities for the next decade.
"We look to see a robust independent assessment of the emissions included with the application - but this issue alone could be a show stopper.
"People have been led to believe the traffic in the town centre would be reduced. This is not the case apart from some reduction on Smithfield Road and that is according to their own modelling.
"Another commonly held misconception is that rat-running through villages to the north west of the town would cease, but again their own model gives only a two-minute time reduction using the proposed relief road instead – hardly a habit changing difference."
"A key document that hasn’t been available before is the Environmental Impact Assessment, hugely important for a scheme that is so environmentally damaging.
"We are also keen to see what is being proposed to protect Shrewsbury’s water supply.
"This threat from the road has rightly been a matter of great concern to both the Environment Agency and Severn Trent Water for many years.
"We believe this road is a hugely expensive, damaging and ineffective scheme which would not help Shrewsbury thrive.
"On the contrary it would be detrimental in so many ways, not least draining council finances, that it would be counter productive.
"We hope a lot of people will put in comments on the planning application when it appears.”
Councillor Steve Davenport, cabinet member of highways and transport, has said while not everyone agrees with building new roads, the positives far outweigh the negatives.
"Ultimately this road will make the town greener, cleaner and will benefit the economy," he said.