Construction could start in spring 2020, with the new £85m road opening in 2022 if government funding is agreed.
The new road will link the A391 at Carluddon with the A30 at Victoria, supporting employment, housing and regeneration in the area.
Cornwall Council said: “The Government has said that, in principle, it’s prepared to contribute £79m to the scheme after a strong funding bid from Cornwall Council to the Department for Transport.
“We’ll now be submitting the final business case to the DfT for release of the funding. The remaining £6m of funding for the new road is coming from Cornwall Council.”
The new road will run from the Singlerose Roundabout south of Stenalees, bypassing to the west of Roche to link to the A30 via the Victoria junction.
Alun Griffiths (Contractors) Ltd, Executive Director Martyn Evans said: “We have considerable experience in delivering sustainable infrastructure projects, identifying all opportunities to enhance social, economic and environmental aspects.
“We are acutely aware of the environmental sensitivities surrounding the scheme and will work in collaboration with all relevant stakeholders to make it a success.
“The Eden Project, through the National Wildflower Centre, has been working with Cornwall Council and partners to change the developmental ethos of road construction to deliver verifiable ecological gain over the longer term, including the creation of wildflower corridors and areas of new habitats.
“We hope that many of the recommendations made within this scheme will become commonplace in any future road building projects.”