March_1966 — Page 80

Edobashi interchange in the centre of Tokyo

a

surveys in early 1952 by the Tokyo

with Metropolitan Government. view to planning an express system that would be most appropriate for the city. Several alternatives for route location of the expressway were proposed and studied by town plan- ners, engineers, architects and cons- truction experts. Five years later, preliminary plans were drafted in col- laboration with the Ministry of Cons- truction. A further two years were spent on extensive research and sur- vey before a final plan was made in 1959.

Forty-four Miles

The total length of the expressway is about 44 miles. Eight routes radiate from the central loop. which circles approximately down- town Tokyo and encompasses a smaller loop. Radiating route No. 1 connects the downtown area and the Tokyo International Airport. It is aimed to extend to the neighbouring city of Kawasaki (population about 1 million) in the near future.

Routes Nos. 2, 3, 4 and 5 connect downtown and subcentres of Tokyo. which have grown rapidly in recent years as residential areas developing from sub-centre in sector form to- wards western suburbs. Three radiat- ing routes towards north and east con- nect downtown with wholesale and industrial areas of Tokyo.

The magnitude of the expressway project as a single public work, re- quired an extensive internal staff re- organisation for either the national or municipal agency. It was there- fore decided to establish an indepen- dent public organisation to undertake this project.

The main reason for the new or- ganisation was its financial advantage.

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fund-raising became

particularly as much more flexible.

In March 1959 the Tokyo Express- way Corporation began to function. Today, the new super highway con- nects Tokyo International Airport to the heart of Tokyo, then goes on to the main Olympic stadiums via the Olympic Village in Yoyogi and ends in Shinjuku, one of the City's metro- politan centres. The section from Haneda Airport to central Tokyo, has a breath-taking view, running along the bay and through the port section.

Coming into the mid-town area, the elevated road drops underground to run along an ancient river bed. In the very centre of Tokyo at Edobashi. has been constructed the largest inter- change in Asia. It sweeps in a vast curve over the Nihonbashi River and then branches off to Route No. 4 straight for the Olympic sites.

Route No. 4 is the shortest link between downtown Tokyo and some of the metropolitan centres further out. This section contains a variety of highway tricks dictated by the ter- rain. In addition to curves, and tun- nels, one will never forget the impres- sion of driving through buildings in Otemachi. over the floating park. through the world's first underground interchange, along tree-lined Benkei- bori, and by the Meiji Shrine.

Speed Limits

The speed limits are 60 km h maximum on straightways and 50 km h maximum on curves and in tunnels. Highway patrol cars make regular rounds to help drivers in dis- tress and keep traffic flowing. The expressway is capable of four-lane traffic.

The speed of 60 km (37.5 miles) per hour may sound extremely low

for an expressway, but higher speed does not necessarily mean more capa- city. In the centre of a large city like Tokyo, there is no need to drive at a speed of 75 miles per hour. The most important function of the route is the smoothest flow of the highest volume of traffic.

During the preliminary study in 1952, various traffic studies were un- dertaken and the results used to for- mulate the expressway system. Among those studies, the 1952 origin/destina- tion traffic survey for the Tokyo Metropolitan area was the most im- portant for route location. Future traffic assignment on the expressway was also estimated,

Part of Plan

In 1958, an origin/destination sur- vey in larger scale was undertaken. Future traffic volume on the proposed expressway was again calculated, this time in greater detail. This later survey consisted of 24 hours of road- side interviews at 19 points on the cordon line around Tokyo's wards area, and of a return postal question- aire of 257,000 car owners in the Tokyo Metropolitan Region.

Actual capacity of the expressway for each section was also calculated, based on given geometric design and Accord- ratio of estimated car types. ing to this calculation 24-hour cap- acity for the four lanes was 60,000

cars.

It has been clearly shown in many large cities that highway improve- ments mean more traffic and that de- pendence on highway improvement alone is not enough. Construction of the expressway project is only part of the planning framework for the city. Tokyo already has an extensive pub- lic transit system, including subway and elevated train lines or monorails which the planners are making strenu- ous efforts to improve. The Tokyo planners believe that mass transit should be their main weapon, but the expressway system is an essential part of the whole.

The Master Plan for the express- way was prepared by the Ministry of Construction and the Tokyo Metro- politan Government, and given to the Tokyo Expressway Corporation for execution. All necessary procedures for construction are the Corporation's responsibility detailed surveying

of planned routes, drawing of plans, numerous detailed engineering draw- ings, land acquisition. legal proce- dures, financing, etc.

Actual construction is undertaken by contractors under the supervision of the corporation's staff.

Each year. the corporation prepares a detailed project plan of the year and submits it to the Ministry of Construction and the Tokyo Metropolitan Government for approval. This enables the two agencies to co-ordinate the express- way with all other public works, and also to review changes found to be necessary by the corporation in carry- ing out its work,

Far East Architect & Builder March, 1966

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