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Braess’s Paradox in South Korea

Every major city has problems with traffic congestion.  Because of the large amounts of people there are large amounts of cars populating the roadways.  It may seem like a logical solution to increase the number of routes cars have access to in order to decrease traffic congestion, but in reality, this makes no difference and can actually worsen the traffic.  Ironically, the actual solution is to eliminate one of the more populated routes and traffic on the alternate routes will decrease. This phenomenon is known as Braess’s Paradox. This seems so counterintuitive to think that getting rid of a freeway can actually speed up traffic, but it relies purely on the principle that the participants, the drivers in this case, act selfishly.  They all want to insure the fastest route for themselves.  If every individual driver has this mentality, then it worsens the traffic for everyone else involved.

Braess’s Paradox is not merely a concept in our course, it can also be demonstrated in real life.  For example, in South Korea a large renovation project addressed a major freeway in Cheonggyecheon. This freeway was not only a major source of traffic congestion in the city, it also was covering a river that ran through the middle of the city.  Korea took it upon itself to completely eliminate this roadway to reveal the river, but their plan was met with much controversy.  No one understood how tearing down a main freeway would eliminate traffic, it was obvious to them it would cause gridlock in other parts of the city.  But relying on the fundamentals of Braess’s paradox to guide them, the construction project continued.  This drastic renovation not only improved the traffic flow in the city, but also created many other positive externalities for the city, some of which include the revival of the river with the creation of a park in place of the freeway and many copycat projects to restore natural areas throughout the country.

In the scenario of Cheonggyecheon, what seemed impossible was achieved and Braess’s paradox was proved.  Drivers in South Korea used to act selfishly and chose individually to all take the same freeway.  With this freeway torn down, they still act selfishly but all of the cars that would have been in traffic jams on the main freeway are now spread onto different road ways in the area. They also now are provided with a scenic walking alternative as well. Overall, Braess’s paradox works because every individual acts only in their own best interests. If every driver instead worked to find the equilibrium of the system and functioned so everyone would have the best possible outcome, in this case the fastest commute time, then everyone would be better off.


Seoul tears down an urban highway and the city can breathe again


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