The A453 is often the scene of congestion
More than £1bn which has been approved for road projects could be better spent elsewhere, it has been claimed.
Funding for schemes including widening the A46 and A453 in Nottinghamshire and Leicestershire has been given the go-ahead by the regional assembly.
But the Campaign to Protect Rural England (CPRE) said greenbelt land will be lost and the money should be used for affordable housing.
Depending on the planning process, the roads could be open by 2011 and 2012.
Upgrading the A453 between Junction 24 of the M1 in Leicestershire and Nottingham is currently predicted to cost up to £194m.
Turning 17.4 miles (28km) of the A46 between Widmerpool and Newark into a dual carriageway is expected to cost about £350m.
Both projects have been proposed for years and have been backed by commuters, businesses and safety campaigners.
But the Campaign to Protect Rural England said the £174m match funding that the region has to provide for the A46 project alone would transform local housing.
Bettina Lange, from the CPRE, said: "You could upgrade 51,000 houses to modern energy efficiency standards, which saves people money as well as fighting climate change.
"Or you could buy 4,500 affordable homes, or you could invest in better rail and bus services."
She added: "You need to assess very carefully whether these huge and hugely expensive road projects really deliver the most benefit."
However Chairman of the Regional Transport Board Nicholas Rushton rejected the suggestion.
"Fifty one thousand houses upgraded and another 4,500 affordable homes aren't what the people of this region want," he said.
"We have campaigned long and hard for this extra money from the government to upgrade this road.
"People are dying on this road, this road will bring massive economic benefits to parts of Lincolnshire and Nottinghamshire and we ought to be proud we have this money which no other region in the country has been successful in getting."
Preliminary work has begun on both projects and contractors will be onsite on the A46 in June.