The Seoul city government said on the 15th that starting at midnight on the 21st it will fully close the Seosomun overpass road and begin demolition work.
The demolition of the Seosomun overpass road is for safety reasons. Completed in 1966, the Seosomun overpass road saw repeated structural damage, including concrete spalling on a pier in 2019, a deck collapse in 2021, and girder damage last year.
A detailed safety inspection carried out in response gave it a "grade D" rating. The safety grades based on this inspection range from A to E, with grade D in the lower tier. It means defects have occurred in key members, requiring urgent repair and reinforcement, and a decision must be made on whether to restrict use.
The Seoul city government plans to finish demolition by May next year. It will then begin new construction, aiming for completion in Feb. 2028.
During the work period, going straight at the intersection from City Hall toward Chungjeongno will be prohibited. Vehicles must detour via nearby roads such as Tongil-ro, Saemunan-ro, and Chilpae-ro. In addition, in front of the Arisu Headquarters under the Seosomun overpass, left turns from Seosomun-ro to Cheongpa-ro will be banned; to enter Cheongpa-ro, continue a bit farther straight and make a U-turn at the crosswalk ahead.
Bus routes will also change. A curbside bus-only lane will be newly installed over a 380-meter section from the Seosomun-ro City Hall Station intersection toward the Seosomun overpass and will operate all day.
Some routes will operate on detours. Since Aug. 17, 20 Gyeonggi and Incheon metropolitan bus routes have begun detouring, and starting on the 21st of this month, 11 Seoul city and late-night bus routes will also operate via Chungjeongno, Sejong-daero, and Tongil-ro.
Five routes that used to make round trips on the existing Seosomun overpass road, including Nos. 172 and 472, will change to Chungjeongno–Tongil-ro–Sejong-daero, and one-way through routes, including Nos. 600 and 602, will change to Sejong-daero–Tongil-ro–Chungjeongno.
Detailed detour routes can be found on the Seoul city government website, TOPIS, notices at bus stops, and notices posted inside buses.