In the News: Braess’ Paradox and Transportation Networks
A report in England has exemplified how trying to become more efficient is problematic with road network structures. For most people, it is intuitive that in order to reduce traffic, people should build more roads so that the number of drivers on each road would be split (perhaps evenly) among each of the roads.
We can see however that this is not the case. In class we learned that, Dietrich Braess found that adding resources to a transportation network can cause the travel time to increase among drivers. This is otherwise known as Braess’ Paradox. Therefore, achieving equilibrium is more complicated than just adding more resources.
In the article above, the Campaign to Protect Rural England protested the expansion of road building in England last year, claiming that it neither “relieve[s] congestion nor boost[s] local economies.” They were also protesting the expansion of the road building budget. They conducted a study of 86 road schemes and concluded that not only does adding roads increase traffic, but it also destroys the environment (plants and animals and the countryside).
This study has not only reinforced the idea that adding roads is not always beneficial, but has also called attention to the residual economic and environmental effects that aren’t always considered. In such cases, there is often more harm done than good.