National Assembly-daero Underpass and Upper-Level Park Project Gains Momentum... Hongik Hospital Intersection to Close from Oct. 31

'National Assembly-daero Underpass and Upper-Level Park Project' Moves Ahead in Earnest
Measure to Secure Construction Area Under Revised Design for Mokdong Complexes 4 and 7

The Seoul Metropolitan Government announced on the 26th that it will change the traffic system at the Hongik Hospital intersection in Yangcheon-gu as it moves ahead in earnest with the National Assembly-daero Underpass and Upper-Level Park Project.

Aerial rendering of the park above Gukhoe-daero. Seoul Metropolitan Government

The National Assembly-daero Underpass and Upper-Level Park Project will build a 4.1-kilometer underpass along a total 7.6-kilometer stretch from Sinwol IC in Yangcheon-gu, Seoul, to the National Assembly Building intersection, diverting vehicle traffic underground. It will also reconfigure the road space along a 3.5-kilometer section to create a linear park of approximately 110,000 square meters above ground.

To begin construction, the Seoul Metropolitan Government will close the underpass beneath the Hongik Hospital intersection at 7 a.m. on October 31.

Traffic will shift from the existing six lanes—four above ground and two underground—to a seven-lane, at-grade intersection. The city increased the number of lanes by adjusting the sidewalks and roadway to secure additional road space.

This change to the traffic system is intended to secure the construction area needed to build the underpass, in line with the revised design for the section by Mokdong Complexes 4 and 7.

The city initially planned to build the project by installing a cover over the existing underpass in the section by Mokdong Complexes 4 and 7. However, residents raised concerns that this approach would create a level difference of approximately 3 meters, making the park difficult to use.

In response, the city revised the design to build the underpass deeper than it is now and create a level surface above ground.

The city will also take steps to reduce inconvenience during the traffic system change, including improving intersection signal systems and securing temporary lanes.

To protect pedestrians, two-stage crosswalks will be operated at north-south crossings, allowing pedestrians to wait once in a central refuge before crossing.

During rush hours, the city plans to deploy traffic control personnel and pedestrian assistants at major intersections to strengthen traffic management and pedestrian safety.

The city is pursuing the National Assembly-daero Underpass and Upper-Level Park Project with the goal of opening the underpass in June 2031 and completing the upper-level park in June 2032.

Once completed, the project will create green space above National Assembly-daero equivalent to about three times the size of Gwanghwamun Square and about eight times the size of Seoul Plaza.

The area will include a large lawn and a community center, allowing residents to enjoy walks, relaxation, and cultural activities.

The upper-level park along National Assembly-daero will serve as a key link in a green and waterfront network connecting Seoseoul Lake Park, Anyangcheon Stream, and the Han River. It is expected to help improve the living environment in southwestern Seoul, including Yangcheon-gu, Gangseo-gu, and Yeongdeungpo-gu.

“This traffic change is part of an effort to improve vehicle traffic capacity by building the National Assembly-daero underpass and to create green and recreational spaces centered on residents above ground,” said Lim Chun-geun, head of the Seoul Metropolitan Government’s Urban Infrastructure Headquarters. “We ask for the public’s understanding and cooperation as we closely monitor traffic conditions and strengthen on-site management to minimize inconvenience.”

This content was produced with the assistance of AI translation services.