The Transport Ministry plans to build two new elevated tollways, Pathum Thani-Ayutthaya and Nonthaburi-western Bangkok, at an estimated total cost of 87 billion baht.
Transport Minister Suriya Juangroongruangkit said on Monday one project would be a north-bound extension of the Don Muang tollway, from Rangsit area in Pathum Thani to Bang Pa-in district of Ayutthaya.
The new elevated tollway would cost an estimated 31.28 billion baht and be 22 kilometres long.
The private sector would be invited to tender for the construction of the new tollway and its operation, and the state would repay the cost later.
The other project was for an elevated 35.85-kilometre tollway above the existing western outer ring road of Bangkok, between Bang Khunthian district and Bang Bua Thong district of Nonthaburi. The construction cost was estimated at 56.03 billion baht.
Mr Suriya expected the two new tollways would open in 2028.