The Traffic Assignment problem consists in determining the routes used by sets of network users taking into account the link congestions. In deterministic modelling, Wardrop Equilibriums are computed. They can be reduced to huge non-linear multiflow problems in the simplest cases. In stochastic modelling, Logit Assignments are used. They are obtained, mainly, by substituting the minplus semiring by the «Gibbs-Maslov semirings»[ ], in the deterministic assignment computations.