On the Price of Anarchy of Highly Congested Nonatomic Network Games
  We consider nonatomic network games with one source and one destination. We examine the asymptotic behavior of the price of anarchy as the inflow increases. In accordance with some empirical observations, we show that, under suitable conditions, the price of anarchy is asymptotic to one. We show with some counterexamples that this is not always the case. The counterexamples occur in very simple parallel graphs. 
Riccardo Colini-Baldeschi, Roberto Cominetti, and Marco Scarsini
cs.GT math.OC