More than 100 people attended the official opening of the Dobwalls Bypass yesterday (Thursday).
Transport Minister Paul Clark unveiled a plaque to commemorate the opening and a tree was planted at the site near the Toll House, Moorswater.
Mr Clark was helped with the planting of the tree by 11-year-old Jessica, a pupil from Hillfort Primary School in Liskeard.
The £54m project has already reduced traffic through the village by 90 per cent and will significantly reduce delays, particularly during the peak holiday periods.
Mr Clark said: 'I am delighted that it has brought a big improvement in quality of life for the community since traffic started using the new road.
'The bypass also improves transport links for local businesses and will be a welcome boost to thousands of holidaymakers who come to Cornwall during the summer months.'