Group plans to bury Tokyo's elevated 'shuto'

A group of business executives is floating the idea of burying all of Tokyo's elevated highways 60 meters underground. The megaproject also includes a sweeping greening of the space they will leave behind and large-scale redevelopment at key highway ramps.

Nihonbashi Bridge, the starting point for five major trunk roads in the Edo Period and one of Tokyo's historical landmarks, is overshadowed by an elevated expressway. A government panel proposed in fall 2006 to then-Prime Minister Junichiro Koizumi to put a 2-km section of the expressway underground, and build a park and promenade near the bridge. The project remains stalled due to its huge cost — estimated at between 400 billion yen and 500 billion yen. KYODO PHOTO

The project is the brainchild of Keiei Doyukai, which was established in 1962 as a forum for exchanges among young entrepreneurs and owners of midsize businesses, including some companies listed on the Tokyo Stock Exchange.

Yoshitaka Ohashi, an executive of the group, said, "The proposed deep underground expressways in Tokyo's city center would not only help to reduce chronic traffic congestion but serve to improve the urban environment."

But this is not as revolutionary as it may sound. Indeed, Tokyo is already going deep underground.

In 2000, a new subway line was opened as an addition to the weblike Tokyo Metropolitan Subway system. The Oedo Line runs about 50 meters below the surface at its deepest point.

In December, Metropolitan Expressway Co., operator of metropolitan highways, completed a 7-km-long section of the Central Circular Route of the expressway network, linking Shinjuku and Itabashi, in the 30-meter-deep Yamate Tunnel.

Construction is under way to extend this highway tunnel from Shinjuku to Shibuya. The 4-km section is to be completed for public use in fiscal 2009, ending in March 2010, with the entire 47-km-long Central Circular Route due for completion in fiscal 2013. This route runs through the outer wards of Tokyo, some 8 km from the capital's epicenter.

According to Metropolitan Expressway, more than 73 percent of the new expressways, either under construction or in the planning stage, are underground, with the rest being elevated or on the surface.

However, the expressway operator has no immediate plans to renovate the aging elevated sections of the network in the heart of Tokyo, which is officially called the Inner Circular Route, the target for the group's project.

These sections, totaling 32.5 km in length, were built between December 1962 and July 1967, or in the period of Japan's frenetic economic growth and construction boom, which peaked with the 1964 Tokyo Olympics. And as is obvious from the frequent maintenance work that clogs traffic flows, they are decaying.

An official of the PR office at Metropolitan Expressway, which was privatized in fall 2005, admitted that the expressways in question are decrepit, but the company doesn't have the money to renovate them. "All we can do is repair the old highways in a regular and systematic manner, and ensure safety for drivers and prolong their service life as much as possible," the official said.

What is unique about the proposal by Ohashi's group is that it uses the new legislative framework for "deep underground" utilization for public works and does not count on state coffers to finance the project.

Plans to bury infrastructure, ranging from key lifelines and commercial centers to roadways and rail links, deep underground and free up space on the surface for urban redevelopment, flourished during the development-at-all-costs 1980s.

Most of those plans disappeared in the wake of the collapse of the economic bubble and the ensuing economic doldrums of the 1990s, Japan's "lost decade."

In 2001, however, the Diet passed legislation that legalized deep underground development beneath major cities. The zone, more than 40 meters below ground or 10 meters beneath the bearing stratum of existing buildings, is now open to public-works projects free of charge and without prior permission from landowners on the surface.

According to the group's draft proposal, all of the existing elevated Inner Circular Route of the Metropolitan Expressway system will be buried to a depth of 60 meters. "By applying the deep underground utilization law to this megaproject, there is no need to worry about the huge cost of procuring land, which usually accounts for a large portion of the cost estimates for any public-works project — 80 percent to 90 percent in some cases," Ohashi said.

More important, construction time for this project is estimated to be only two to three years, much shorter than the 10 years needed to complete a project of similar scale, by fully utilizing Japan's state-of-the-art shield tunneling method. "Indeed, the level of Japan's civil engineering technology is the highest in the world," Ohashi boasts.

An estimate for this megaproject, consigned to a leading construction consultancy, shows that the total construction cost would be approximately ¥1.7 trillion to ¥2 trillion, including the cost of dismantling existing structures on the surface.

According to the estimate, the benefit-cost ratio of the proposed project is 1.6, meaning that benefits would surpass costs in the long run. The ratio is a meager 1.1 for many public-works projects.

The cost estimates premise maintenance fees amounting to about ¥7.3 billion a year and an increase in traffic volume on the expressway section by 20 percent to 30 percent.

Another feature of the proposal is the introduction of the private finance initiative (PFI) method for this project. In other words, this project is financed 100 percent by the private sector without relying on taxpayers' money, although users would have to pay a toll to use the underground highways.

The group claims that the profitability of the undertaking is quite high. "We could redeem the invested capital of ¥2 trillion in less than 20 years as this project is expected to generate ¥200 billion a year in revenue and its running costs will be only ¥10 billion a year," Ohashi predicted.

In addition, the removal of the elevated highways in the heart of Tokyo would pave the way for sweeping urban renewal or redevelopment projects with their spinoff effects estimated to be worth ¥2 trillion to ¥3 trillion, or 0.5 percent of the nation's gross domestic product, according to the group.

Aside from the economic aspects of this project, its positive impact on Tokyo's living environment is immeasurable. The empty space could be turned into parks or streams to reduce carbon dioxide emissions while car exhausts would be cooled and purified underground for release into the air, according to the proposal.

However, it is open to question whether the current operator of the metropolitan expressways will agree to abandon part of its business for the sake of this project. Government red tape and mobilization of private interests for this undertaking are also uncertain factors.

But Ohashi and other key members of the group seem undaunted.

"Imagine the heart of Tokyo without the network of elevated highways, the source of noise and exhaust emissions. This is a dream project, the ultimate aim of which is to create a better and eco-friendly urban environment in Tokyo for generations to come," he said.

For further information on the group's proposal, visit its Web site (www.keieidoyukai.com).