Tokyo Expressway (KK Line)

A free elevated expressway through central Tokyo's Ginza and Kyobashi districts, open from 1959 and decommissioned in April 2025 after 66 years of service. Its viaduct is now being converted into a public green promenade under the Roof Park Project.

Use

Office tower

Area

Chuo City / Chiyoda City

Completed

1966

Tokyo’s Free Inner-City Highway

Threading through the Ginza and Kyobashi districts, the Tokyo Expressway — universally known in Tokyo as the KK Line — was one of the city’s most unusual pieces of road infrastructure. The first section opened in 1959, the full approximately 2-kilometer route was complete by 1966, and for 66 years it carried traffic free of charge through central Tokyo’s most expensive real estate.

What made the KK Line distinctive was not just its location — threading between buildings at second-floor height, running over former watercourses including the Shiodome River and the Kyobashi River — but its funding model. The operator, Tokyo Expressway Co., Ltd., owned the land beneath and alongside the viaduct and paid for maintenance out of rental income from commercial tenants in the ground-floor storefronts built into the expressway’s base structure. This made the KK Line simultaneously a road and a landlord, a configuration unlike any other highway in Japan.

From Viaduct to Urban Park

On April 5, 2025, the KK Line closed to vehicles. Tokyo and the operating company have announced the Roof Park Project: a plan to transform the 2-kilometer viaduct into a continuous elevated promenade, lined with greenery and connected to the Ginza, Higashi-Shimbashi, and Kyobashi neighborhoods below. The concept draws inevitable comparison to New York’s High Line — a disused elevated rail track converted into a wildly popular linear park that revitalized the Hudson Yards and Chelsea neighborhoods — though the KK Line’s urban context is denser and more commercially embedded.

The transformation from road to park changes the character of the infrastructure without erasing it: the concrete piers, the gradients, and the overhead clearances that shaped 66 years of Tokyo driving will all persist in the landscape of a pedestrian route above the city.

Summary

The Tokyo Expressway (KK Line) opened its first section in 1959, reached full length in 1966, and closed on April 5, 2025, after 66 unbroken years as a free, elevated commuter route through the heart of Ginza and Kyobashi. Its second life as a rooftop public park is now underway, promising a new way to experience a part of central Tokyo that most visitors see only from ground level or a taxi window. Walking the route when the Roof Park opens will be a chance to stand above Ginza’s streetgrid, looking out over a city that is still actively reshaping its own infrastructure.

For the broader story of how Tokyo has managed and reimagined its elevated expressways, the C1 Metropolitan Expressway article traces a parallel history just one layer outward from the KK Line.