Seoul will temporarily open the Daemo Underpass, a new underground road built to ease chronic congestion on Yangjae-daero, starting at 11 p.m. Saturday, the city said. The 1,174-meter, four-lane underpass runs beneath Yangjae-daero between the Guryong-maeul entrance intersection and the Gaepo 3rd and 4th Complex intersection in southern Seoul's Gangnam area, directly linking two existing underpasses, Guryong and Ilwon, along one of the city's busiest sections of road. Yangjae-daero is a major east-west corridor connecting the Gangnam Beltway, an urban expressway that loops around southern Seoul, with the Gyeongbu Expressway, the country's main north-south highway to Busan. Heavy traffic has long caused backups at its main intersections, prompting the city to build a series of underpasses in stages: The Guryong underpass opened in September 2014, the Yeomgok-dongseo underpass in December 2019 and the Maeheon underpass in late 2020, while the Ilwon underpass has operated since December 1993. With the Daemo underpass opening, the underground route linking Maeheon, Yeomgok-dongseo, Guryong,