Editing Braess's paradox (section)

=== Prevalence ===
In 1983, Steinberg and Zangwill provided, under reasonable{{third-party inline|date=August 2024|reason=An old paper proving theorems about a model doesn't seem like a great source for the reasonableness of that model. This also seems like an extraordinary claim.}} assumptions, the necessary and sufficient conditions for Braess's paradox to occur in a general transportation network when a new route is added. (Note that their result applies to the addition of ''any'' new route, not just to the case of adding a single link.) As a corollary, they obtain that Braess's paradox is about as likely to occur as not occur when a random new route is added.<ref>{{Cite journal | doi = 10.1287/trsc.17.3.301| title = The Prevalence of Braess' Paradox| journal = Transportation Science| volume = 17| issue = 3| pages = 301| year = 1983| last1 = Steinberg | first1 = R. | last2 = Zangwill | first2 = W. I. }}</ref>