On side constrained models of traffic equilibria

The basic model of traffic assignment does not capture complex traffic flow relationships such as interactions among vehicles on different road links, joint capacities on two-way streets, turning priorities in junctions, etc. Traditionally, such relationships are introduced implicitly through generalizations of the separable travel cost function of the basic model, and the refined models are usually stated as variational inequalities. However, this approach has found very little practical use, seemingly mostly because the generalized travel cost functions are not easily chosen and calibrated.