Delay for N1 expressway tunnel option

The Expressway Authority of Thailand (Exat) is likely to scrap a proposal to build an underground route to replace a controversial section of the N1 Expressway development after questions were raised about its financial viablility.
Exat governor Surachet Laophulsuk said Exat’s board has acknowledged the agency’s decision to delay the project which is based on the findings of a study.
Although the equity internal rate of return (EIRR) is estimated at 19.2%, the financial internal rate of return (FIRR) is negative, indicating high project costs, he said.
Mr Surachet said the costs, estimated at 50 billion baht, are high because the project involves building an underground route to minimise environment impacts. However, as the project’s financial return rate is negative, the project should be delayed unless the route is changed to an elevated route, he said.
The matter will be forwarded to the Transport Ministry and cabinet. Mr Surachet also said Exact plans to seek cabinet approval later this week for two other projects: an 11.3km section of an expressway known as N2 Expressway and a 3.98km tunnel in Phuket.
The N2 Expressway project (Prasertmanukit Road-Outer Eastern Ring Road) is estimated to cost 16.96 billion baht while the tunnel linking Kathu with Patong in Phuket is estimated to cost 16.19 billion baht.
Based on the feasibility of the N1 Expressway scheme, the total project costs are estimated at 49.22 billion baht. Of this amount, 44.5 billion will be spent on construction, 3.6 billion baht on land expropriation costs, and 1.06 billion baht on construction supervision.
At a public hearing on July 13, most participants opposed the underground route due to high costs and scepticism the project could actually alleviate traffic congestion.
The underground route was chosen to replace the controversial section following discussions with Kasetsart University and communities along the route.
Exat previously said the agency had considered several aspects, including engineering, investment costs, and the environmental impacts, and found the underpass to be the most feasible option.
The 6.3-kilometre structure would run along Ngam Wong Wan Road via Phongphet intersection, Bang Khen intersection, and Kaset intersection to Prasertmanukit Road before connecting with the N2 Expressway.
The N1 Expressway is expected to shorten travel time from the eastern part of the Bangkok to the western part by 30 minutes.