In one of his lecture, Dr. Easley briefly mentioned about the Seoul’s restoration of Cheonggyecheon which was used as an example of Braess’s Paradox. It is amazing to know that removing a highway actually increases the flow of traffic in that area. But it seems to be that there has to be an additional factor that caused the flow of traffic to increase.
Before Cheonggyecheon was restored, Seoul’s traffic was in turmoil. Especially, according to the report, the bus system was caught in a ‘lasting of vicious circle’ in which profit was obtained by based on the number of passengers. However, after the reform was conducted, bus companies gained their profit based on their service result based on the number of services and distances. Because the income structure has been changed, Seoul was able to transform the overall bus system of the metropolitan area.
When the bus system went under transformation, many bus routes have been changed, diminished, or newly formed. And new technologies and strategies have been adapted to the plan. Among the new strategies, another example of Braess’s Paradox was observed. For the bus system, Seoul divided bus routes into four subsystems: main line, branch line, wide area line, and circular line. The significance of these divisions is that it prevented different buses to share the same route; it also diminished many popular routes that attracted many passengers. As a result of preventing passengers being gathered in one area, flow of the bus system was able to be normalized without creating any heavy traffic jams. In addition, since each subsystem occupies its own area and route which the bus can serve to the public, bus companies do not need to compete for the routes in order to gain their profits.

Image: in Seoul, middle lanes of boulevards are served as bus-only lanes.

Another significant factor which contributed to the flow of the public transportation was Seoul’s adaption to the new fare payment system. The use of transportation card which is also known as T-money increased the flow velocity of people in using public transportations. After Seoul adapted this system, many buses were able to spend less time on waiting for the passengers to get on the bus. For this reason, this may have been also a reason for increasing the flow of bus traffic in Seoul.
In addition to Cheonggyecheon restoration project as an example of Braess’s Paradox, the Seoul bus system reform can also be an example of this kind of paradox. Observing the bus system reform, it seems to be that removing a major motorway in the downtown area may have not been the only factor that caused the increase of traffic flow. The improvement of the bus system attracted many Seoulites getting on the bus rather than going in their cars.
Link: http://samaw.com/seoul-bus-transport-reform/2108