A 35-km section of Highway 1 that runs through central Ha Tinh province opened to traffic on January 19.
The six-lane section runs from the province's Xuan Vien commune in Nghi Xuan district to Thach Viet commune in Thach Ha district and includes nine bridges.
The 2 trillion VND (94 million USD) build-operate-transfer construction was built by the Ministry of Transport's Civil Engineering Construction Corporation 4 as part of an overall project to expand National Highway 1 by 2016.
It was completed in 16 months, nine months ahead of schedule, and this was applauded by Deputy Transport Minister Truong Tan Vien.
"The project's implementation is a good experience in site clearance and construction safety," he told radio The Voice of Vietnam (VOV).
National Highway 1 runs through 31 provinces and cities, from Huu Nghi Border Gate in northern Lang Son province to southernmost Ca Mau province.
By expanding it, authorities hope to reduce traffic accidents and congestion and promote the country's social and economic development