On April 4, the Busan mayor and city officials inspected the construction of the Busan Manduk Centum Expressway, an underground road built at a depth of 40 meters, shortly before its opening on April 10. This road passes through a section currently at a depth of 60 meters, which the supervising engineer stated was particularly challenging to construct. The tunnel features an air purification system and a large iron door that can be opened in emergencies, providing an escape route to the opposite lane.

The Manduk Centum Expressway, spanning 9.62 kilometers from Manduk-dong to Jaesong-dong in Busan, is notable not only for being Korea's third underground road but also for being the first that accommodates all vehicle types outside of the capital region. Construction began in November 2019 and was finalized in January 2023, taking 6 years and 3 months to complete. The project had a total cost of approximately 791.2 billion KRW, financed through a mix of private investment and public funds.

In contrast to previous similar projects in Seoul, which restricted passage to only small vehicles, this expressway is designed with safety features to handle major incidents such as fires or floods, including automatic sprinklers that activate in the presence of smoke. This development is crucial not only for enhancing transportation efficiency in Busan but also signifies a progressive step in infrastructural capabilities related to urban planning in South Korea.