Is the assumption inappropriate for calculating the cost-effectiveness of the Hokuriku Shinkansen extension route? The ruling party chose the Obama-Kyoto route.

The basis for the rough cost-benefit (B/C) calculations that the Ministry of Land, Infrastructure, Transport and Tourism presented to the ruling party during the discussion on the extension route of the Hokuriku Shinkansen has been revealed. The Asahi Shimbun obtained and analyzed the materials presented by the Ministry of Land, Infrastructure, Transport and Tourism to some members of the ruling party's Diet.

Based on this calculation, the ruling party decided to proceed with the plan using the Obama-Kyoto route (Katsuragawa's plan). However, in the calculation process, it was assumed that the cost would increase for options other than the Obama-Kyoto route, leading to an unfavorable result. Several experts have called it ``inappropriate.''

Regarding the Hokuriku Shinkansen line between Tsuruga and Shin-Osaka, the ruling party's development committee consisting of the Liberal Democratic Party and the Nippon Ishin no Kai has been discussing eight possible routes since December last year. The Ministry of Land, Infrastructure, Transport and Tourism presented a B/C for the entire route in June this year. It was the first time in 10 years that the government presented a B/C regarding the Hokuriku Shinkansen project.

“Reversal” that occurred at B/C

When B/C exceeds 1, it means that the benefits exceed the costs, and is considered a green light for construction to begin.

In the "individual evaluation" that only covers the Tsuruga-Shin-Osaka route, the Obama-Kyoto route (Katsuragawa plan), which was promoted by the Liberal Democratic Party, has a B/C of 0.5, which ranks it fourth from the top. This was lower than the 0.7 of the Maibara route (partially direct route) promoted by the Meiji Restoration.

The Ministry of Land, Infrastructure, Transport and Tourism has not released details, but according to explanatory materials shown to ruling party members, the Katsuragawa plan has a total cost of 1.92 trillion yen and an effect (total benefit) of 1.2 trillion yen. Yonehara's partial direct line plan would cost 1.23 trillion yen and have an effect of 880 billion yen.

On the other hand, in the latest calculations, it was found that costs such as communication and coordination costs with the Nishi-Kyushu Shinkansen (Nagasaki route), which was already under construction, were not added only to the Katsuragawa plan, but were unnaturally added to other routes. As a result, the costs of other routes were estimated to be higher than they actually were, and adjustments were made to make the Katsuragawa plan appear more advantageous.

Experts point out that such a preface is inappropriate as a cost-benefit analysis and harms the fairness of policy decisions. Although the Ministry of Land, Infrastructure, Transport and Tourism acknowledged the existence of explanatory materials, it has not made public the detailed calculation process.