高速道路60年史 the 60-year history of Yokohama motorway

金近忠彦氏講演会 概要

20231122日(水)午後6時~845

なか区民活動センター研修室1

参加者:講師1名、聴衆5名、計6

 

衝撃的な講演内容だった。歴史的事実の研究は多角的にアプローチしないと、見誤ることになりかねない。どの専門分野でも暗黙知がある、それを持たない専門外の人間には伺い知れないものがあることを実感した。

 

首都高速道路の地下化とベイブリッジについて金近氏は語ったが、その背景となる組織間の関係や有力人物の関与などが主たる内容だった。高速道路地下化は1968年からわずか一年間で決着した前代未聞の事案であり、それに係わった組織間の調整は困難なものであった。当該事案については田口俊夫による研究論文(日本建築学会計画系論文集,769巻号,p.603-613,2020-03、土木学会論文集,Vol.79,No.9,22-00290,2023)があるが、不確かであった「国と市の費用分担の件」について、道路専門家である金近氏の解説がおおいに参考となる。

 

地下化交渉が開始するには、建設省から求められた費用増加分を横浜市が受け持つ必要があった。田口はその負担分を、首都高速道路公団に対する横浜市からの「出資金」で賄った、と類推した。金近氏は派大岡川埋立て上部(地下に高速道路)と既存側道を使った関連街路事業(市道整備)で、対応したと結論づけた。つまり、企画調整室の「経緯メモ」に記載されていない市道路局高速道路課(池澤利明課長)の決断があったとしている。

池澤は「地下化の立役者」といわれる企画調整室部長の田村明と対立しており、建設省寄りと見られていた。この池澤が飛鳥田市長の地下化方針に従い、調整役を果たした。地下化の経緯は田口論文にあるように、吉田川での高速道路との共存による地下鉄工事への甚大な影響を被る運輸省の猛反発で、建設省も政治交渉で妥協する。ただし、派大岡川での決着がなければ吉田川での交渉に進めなかった。因みに、池澤は自宅に、飛鳥田と一緒に撮った当該関連街路事業の完成式典の写真を生前飾っていた。

田村の著書によれば、地下化事案によって建設省は横浜市に禍根を残すことになったと読める。金近氏によれば、組織間で正式に決着した(建設事務次官と市長)事案で禍根を残すことはありえない、という。別に、禍根を残す大きな事案があった。それが、市が米軍戦車を止めた「村雨橋事件」である。19728月に車両制限令(道路管理者による通行する車両の幅・重量・高さ・長さ等を制限する政令)を根拠に、20トン制限の橋に100トン近い戦車輸送車を通せないとした。飛鳥田市長に率いられたデモ隊が、10月に閣議決定で政令が改定(非常時の自衛隊車両と駐留米軍に非適用)されるまで通行を阻止した。革新市政のおおきな実績となったが、国政を巻き込む一大事件であった。これによって、「横浜市は独立国か」と国の官僚に揶揄される。独立国なら国からの補助金もいらないだろう、という論理となり、本来出るべき補助金を渋られる事態が続いていく。それが改善されるのが、飛鳥田以降の細郷道一市政(元自治事務次官)になったからのことである。ベイブリッジ事業はこのため、計画と設計が飛鳥田市政で完了していたにもかかわらず、事業化の目途がつかなかった。

 

そして、車両制限令の知恵を飛鳥田市長に出した池澤は、飛鳥田市政で何度も国会への陳情団を組織したが、国は聞き置くだけで効果がまったくなかった。また、NHKによる番組「プロジェクトX」でベイブリッジが取り上げられ、その立役者が田村明でなく池澤となっていたことに、田村が激怒したことがある。なにしろ、金近氏の講演は、政策がどう立案され事業化されていくかについて、国と地方の政治家と官僚が係わる「仕組み」が垣間見せた。くれぐれも、当該講演録の校正で、現役の官僚が公開を望まない核心部分が消されないことを願っている。

 

The content of the lecture was shocking. Research on historical facts must be approached from multiple perspectives or it can be misguided. I realized that there is tacit knowledge in every field of expertise, and that there are things inaccessible to people outside of the field who do not have such knowledge.

 

Mr. Tadahiko Kanechika, highway expert, talked about the history of the undergrounding of the Metropolitan Motorway and the Bay Bridge, but he mainly focused on the inter-organizational relationships and involvement of influential people behind the project. The undergrounding of the motorway was an unprecedented project whose planning coordination among the concerned organizations was completed in just one year from 1968. The case was studied in research papers by Toshio Taguchi (Journal of the Architectural Institute of Japan, Vol. 769, p. 603-613, 2020-03, and Journal of the Japan Society of Civil Engineers, Vol. 79, No. 9, 22-00290, 2023). The explanation by Kanechika is very helpful.

 

When starting full negotiations for undergrounding, it was necessary for Yokohama City to share in the increased costs requested by the Ministry of Construction. Taguchi examined that Yokohama City's "deposit" in the Metropolitan Motorway Corporation was used to cover this burden. Kanechika concluded that the city responded by using the upper part of the Haohka River landfill (motorway underground) and related street projects using existing side roads (city road maintenance). In other words, he states that there was a decision made by the Motorway Division of the City Highway Bureau (Toshiaki Ikezawa, section chief) that was not included in the "background memo" from the Planning and Coordination Office.

 

Ikezawa was at odds with Akira Tamura, the director of the Planning and Coordination Office, who is said to be the "driving force behind the undergrounding" and was seen as leaning toward the Construction Ministry. Ikezawa was part of the coordinating body of the undergrounding project by Mayor Asukata. As described in Taguchi's paper, the process of undergrounding was fiercely opposed by the Ministry of Transport, which suffered tremendous impact on subway construction due to the coexistence with the motorway along Yoshida River, and the Ministry of Construction finally had to compromise through political negotiations. However, they could not proceed to negotiations on the Yoshida River without a settlement on the Haohka River. Incidentally, Ikezawa displayed a photo of the completion ceremony of the relevant street project taken with Asukata at his home before his death.

 

According to Tamura's book, the undergrounding project left the Ministry of Construction in a hotly disputed situation with the City of Yokohama. According to Kanechika, it is unlikely for a matter that has been officially settled between organizations (between the vice minister and the mayor) to leave a bad feeling lingered. There was another major case to cause severe frictions between them. In August 1972, based on the Vehicle Restriction Order (a government ordinance issued by the road administrator restricting the width, weight, height, and length of vehicles that may pass on roads), the city stopped a tank carrier weighing nearly 100 tons from passing over a bridge with a 20-ton limit. Demonstrators led by Mayor Asukata blocked the passage until the Cabinet decided in October to revise the ordinance (making it non-applicable to SDF vehicles and U.S. troops stationed in Japan in case of emergency). This was a major achievement of the innovative city administration, but it was also a major incident annoying the national government. This led to the bureaucrats of the national government ridiculing the city, saying, "Is Yokohama an independent country? The logic was that an independent country would not need subsidies from the central government, and the state continued to be reluctant to give subsidies that Yokohama should have needed. This situation was only improved after Asukata was succeeded by Michikazu Saigo, former vice-minister of local government affairs. The Bay Bridge project was thus not on track for implementation, even though the planning and design had been completed during the Asukata administration.

 

Ikezawa, who had presented the wisdom of the vehicle restriction order to Mayor Asukata, organized petitions to the Diet during Asukata’s administration for the Bay Bridge construction, but the state merely listened to him, to no effect. And, Tamura was outraged when the Bay Bridge was featured in the popular television program “Project X” by NHK and Ikezawa, not Tamura, was the architect of the project. Kanechika gave us a glimpse of the "mechanism" by which national and local politicians and bureaucrats are involved in the planning and implementation of policies. I hope that the proofreading of the transcript by the lecturer does not miss any of the important details that current bureaucrats would not like to publicize.