Plans to dual the A30 at Goss Moor in Cornwall could take a step nearer with an announcement by the Chancellor.
If approved, the dualling would include the notorious Iron Bridge
Gordon Brown is due to reveal the government's spending plans for road improvements.
North Cornwall MP Paul Tyler says that if the A30 is not included, there is likely to be a public uproar.
Promising to draw it to the attnetion of government ministers, he said: "There will be a huge protest from all the people of mid and west Cornwall."
The chair of Cornwall's chamber of commerce said the dualling could still go ahead even if it is not mentioned.
David Brewer says it was unlikely the chancellor would refer specifically to Goss Moor in such an important speech.
"Mr Brown will have a long and detailed speech on his spending review and I wouldn't necessarily expect him to mention Goss Moor in that context," he said.
The area being examined is a single lane stretch of the road which is between two dualled sections. Traffic jams on the single lane can last for hours.
The Highways Agency plans to divert and dual the road to ease congestion around the Iron Bridge - a notorious accident black spot.
The scheme has aroused controversy from its inception.
Many people, including Mr Tyler, believe it is vital for the economic future of the county.
However, Goss Moor is an important nature reserve and many environmentalists fear an adverse impact on wildlife.