Why a $600M "3d Bridge" in Salem is both wasteful and counterproductive

Nice Scientific American article that helps explain why Salem needs a third bridge like Custer needed more Indians. (hat tip to Loaded Orygun.) The key idea:

Conventional traffic engineering assumes that given no increase in vehicles, more roads mean less congestion. So when planners in Seoul tore down a six-lane highway a few years ago and replaced it with a five-mile-long park, many transportation professionals were surprised to learn that the city’s traffic flow had actually improved, instead of worsening. “People were freaking out,” recalls Anna Nagurney, a researcher at the University of Massachusetts Amherst, who studies computer and transportation networks. “It was like an inverse of Braess’s paradox.”

The brainchild of mathematician Dietrich Braess of Ruhr University Bochum in Germany, the eponymous paradox unfolds as an abstraction: it states that in a network in which all the moving entities rationally seek the most efficient route, adding extra capacity can actually reduce the network’s overall efficiency. The Seoul project inverts this dynamic: closing a highway—that is, reducing network capacity—improves the system’s effectiveness.

Although Braess’s paradox was first identified in the 1960s and is rooted in 1920s economic theory, the concept never gained traction in the automobile-oriented U.S. But in the 21st century, economic and environmental problems are bringing new scrutiny to the idea that limiting spaces for cars may move more people more efficiently.