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Braess’ paradox or Braess’s paradox is a proposed explanation for a seeming improvement to a road network being able to impede traffic through it. It was discovered in 1968 by mathematician Dietrich Braess, who noticed that adding a road to a congested road traffic network could increase overall journey time, and it has been used to explain instances of improved traffic flow when existing major roads are closed. The paradox may have analogues in electrical power grids and biological systems. It has been suggested that in theory, the improvement of a malfunctioning network could be accomplished by removing certain parts of it.
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