Asymmetric Multiclass Traffic Assignment:
                    A coherent formulation

                 Philippe Toint      Laura Wynter

                          Report 95/13


Behavioural and mathematical  problems in the current formulation
of the asymmetric multiclass traffic assignment model are brought
to  light. A new formulation  is  presented that  resolves  these
difficulties. The formulation is quantified,  and the result is a
general class of coherent, multiclass cost functions. A numerical
calibration exercise for  a car and truck  class  model concludes
the paper.