In this paper we present a version of the (static) traffic equilibrium
problem in which the cost incurred on each path is not simply the sum
of the costs on the arcs that constitute that path. We motivate this
nonadditive version of the problem by describing several situations in
which the classic additivity assumption fails. We describe existence
and uniqueness conditions for this problem, and toe also present conve
rgence theory for a generic algorithm for solving nonadditive problems
.