Officials from the Department of Public Works and Highways said work has been accelerated on the 2.3km tunnel section of the 45.5km Davao City bypass.
The twin-tube tunnel will be the longest in the Philippines and is being constructed by Filipino and Japanese engineers, according to a report on the Inquirer.net news website.
Emil Sadain, public works senior undersecretary, noted that boring has been completed along 264m in one tunnel and 200m in another.
The tunnel runs from the Davao-Digos section of the Pan Philippine Highway in Toril, Davao City, and will terminate at the Davao-Agusan National Highway in Panabo City.
The city covers 2,443km2 making it the largest city in the Philippines in terms of land area. With its population of around 1.8 million, it is the third-most populous city in the Philippines after Quezon City and Manila.
The overall project includes construction of a 7.9km four-lane highway, three bridges, including a 200m crossing bridge of the Davao River, two underpasses and two overpasses. There will also be 12 box culvert waterways and four at-grade intersections.
According to the Department of Public Works, phase one includes 26.5km or roads and bridges, as well as the 2.3lm tunnel, and improvements to 10.2km of existing connecting local roads.
Phase 2 includes just under 16km of roads and bridges.
The department said that the first phase of the project is expected to cost US$273.3 million with a some of the funding provided by the Japan International Cooperation Agency (JICA). The contract for the first section of the bypass is being done by two Japanese construction companies - Takenaka Civil Engineering & Construction and Shimizu and Ulticon Builders.
At the time of the contract award the department said that tunnel construction would be one of the most challenging portions of phase one of the bypass project. But once the entire project is completed in 2027, the bypass will slash travel time between Toril, Davao City and Panabo City, Davao Del Norte, to under 49 minutes from the usual time of 1 hour and 44 minutes via the Maharlika Highway.