The government plans to keep close tabs on 37 New Town areas bogged down by heavy traffic.
A committee under the transport ministry announced the designation on Wednesday. Residents have to endure hellish gridlocks in their commutes to and from infamous areas such as Dongtan in Hwaseong and Homaesil in Suwon.
The government will start by introducing short-term measures such as boosting bus operations.
Some of these newly developed areas on the traffic blacklist saw rail projects delayed by more than a year even as new tenants started to move in or are expected to in the next year.
For these areas, the ministry will add more intercity bus routes, and introduce charter bus services as well as double-decker electric buses during rush hour.
The cities will also increase intracity and shuttle bus operations while a Demand Responsive Transit system will boost flexibility and help ease rush-hour bottlenecks.
Boosting bus routes and frequency will serve as an immediate solution as rail and subway operations take longer to start operations.