The proposal was discussed at a meeting between the Phu Tho and Thai Nguyen authorities on August 5.
According to the project proponent, the VND 5.8 trillion project would receive about 50 per cent of its funding from the state budget, with the remainder mobilised through private investment. The concession period is estimated at 30 years.
The preferred option would build a 2-kilometre tunnel through the Tam Dao mountain range as part of an 18.8-kilometre route linking the eastern and western slopes.
The route is expected to provide the shortest road connection between Thai Nguyen, Phu Tho and Hanoi, while reducing environmental impacts compared with alternative alignments.
Authorities from both provinces reviewed the proposed route, technical solutions, financing, land clearance, forest protection and compliance with existing planning.
Tran Duy Dong, Chairman of the Phu Tho People's Committee, said the project would strengthen regional connectivity, attract investment and support tourism and socio-economic development in both provinces.
His counterpart in Thai Nguyen, Vuong Quoc Tuan, said the tunnel would improve transport capacity and create a direct road link between Thai Nguyen, Phu Tho and Hanoi.