Seoul City Launches Underground Project for Dongbu Expressway... Completion in 2028

The underground construction project of the Dongbu Expressway from Wolreunggyo to Daechi-dong (Daechi Woosung Apartment Intersection), totaling 12.2 km, will commence in the second half of this year. Once the underground road is completed, travel time between the southeast and northeast areas is expected to be reduced by about 20 minutes.

On the 27th, the Seoul Metropolitan Government announced that it has selected the Daewoo Construction consortium as the operator for the ‘private investment project’ section (Wolreung to Samsung) of the first phase of the Dongbu Expressway underground project and will sign an implementation agreement. The city received proposals for the private investment project in August 2015, completed the private investment feasibility study by the Korea Development Institute, designated the preferred negotiator, conducted practical negotiations, and after review by the Private Investment Project Deliberation Committee in December last year, it is now signing the implementation agreement.

The Dongbu Expressway underground project aims to separate long- and short-distance traffic on the existing Dongbu Expressway by constructing a deep four-lane underground road (tunnel) from Wolreunggyo to Daechi-dong (Daechi Woosung Apartment Intersection) and undergrounding the existing Dongbu Expressway section. Construction will be promoted by dividing the project into private investment and public finance sections.

Seoul City is promoting the project in two phases, comprehensively considering traffic conditions on the Dongbu Expressway and Yeongdong Boulevard sections, the city’s financial situation, and project objectives. In the first phase, a deep underground road for traffic improvement (Wolreung to Daechi, 12.2 km) will be constructed by 2028, followed by the second phase, which will underground the existing Dongbu Expressway section (Wolgye to Songjeong, 11.5 km).

The ‘private investment project’ section of the first phase is a 10.1 km long, four-lane underground road exclusively for small vehicles, passing under Jungnangcheon Stream and the Han River. Access and exit are possible via the existing Dongbu Expressway Wolreung IC and Gunja IC, and new interchanges will be established at Samsung IC on Yeongdong Boulevard and Cheongdam IC on Dosan Boulevard.

Additionally, the public finance section on Yeongdong Boulevard (Samsung to Daechi), funded by the city, completed contractor selection in February and is scheduled to start construction in the first half of the year, aiming for simultaneous opening with the private investment section in 2028. The city expects that once the Dongbu Expressway underground road is completed, about 70,000 vehicles per day will be diverted underground via the four-lane underground road directly connecting Seokgwan-dong (Wolreunggyo) to Daechi-dong, alleviating surface road congestion.

Furthermore, travel time between the southeast and northeast areas will be reduced from about 30 minutes to 10 minutes, and by spreading the effects of the Southeast International Exchange Complex District to the northeast area, it is expected to contribute to balanced regional development.

Meanwhile, Seoul City will conduct a feasibility study this year on the 3.0 km connecting section between the end of the Dongbu Expressway underground section at ‘Daechi Woosung Apartment Intersection’ and the ‘Seongnam-Gangnam Expressway terminus’ (Ilwon-dong Ilwon Tunnel Intersection), and actively cooperate with the Ministry of Land, Infrastructure and Transport, the project authority of the ‘Seongnam-Gangnam Expressway,’ aiming for simultaneous opening with the private investment section in 2028. The ‘Seongnam-Gangnam Expressway’ is a project to construct a 9.5 km, four-lane expressway connecting Geumto-dong, Sujeong-gu, Seongnam-si, Gyeonggi-do to Ilwon-dong, Gangnam-gu, Seoul.

Choi Jin-seok, Director General of Safety at Seoul City, said, “The undergrounding of the Dongbu Expressway will resolve chronic congestion and directly connect the main roads of the northeast and southeast areas, spreading the effects of the Southeast International Exchange Complex District to the northeast area and promoting balanced development between Gangnam and Gangbuk. We will make every effort to ensure the project becomes a pivotal transportation route connected to the Gyeongbu Expressway and others.”