A third direct road connecting Seoul and Incheon will be built for the first time in 60 years. The Incheon Metropolitan Government announced Monday that the Fourth Gyeongin Expressway private investment project passed the private investment feasibility review. The project carries a total cost of 1.8015 trillion won ($1.3 billion), with groundbreaking targeted for 2030 and opening for 2035.
The Fourth Gyeongin is an alternative to the chronically congested Gyeongin Expressway. According to Korea Expressway Corporation, the Gyeongin Expressway recorded an all-time high average daily traffic volume of 191,301 vehicles in 2024. That figure surged 47% from 130,000 in 2016 over eight years. With 96,000 vehicles heading toward Incheon and 95,000 toward Seoul, both directions exceed design capacity. The expressway has effectively lost its function as a highway during rush hours.
Since the First Gyeongin Expressway opened in 1968, only two roads have directly connected Seoul and Incheon: the First Gyeongin and the Second Gyeongin (opened in 2000). The Third Gyeongin Expressway (2017) links southern Incheon to Ansan, so it failed to divert demand for direct Seoul-bound routes. The opening of the Fourth Gyeongin will add a direct Seoul route for the first time in 25 years.
Economic viability has also been confirmed. The Public and Private Infrastructure Investment Management Center (PIMAC) under the Korea Development Institute found a benefit-to-cost ratio (B/C) of 1.25 in its private investment feasibility review. A ratio above 1.0 is considered to justify investment. Traffic on the Gyeongin Expressway is projected to decline 10.2% and on the Second Gyeongin Expressway 13.2% by 2035. Peak-hour travel time from Incheon Port to Gangnam will be cut by 25 minutes, from 97 minutes to 72 minutes.
