  This technical note concerns the dynamics of FIFO-diverging junctions in
compartmental models for traffic networks. Many strong results on the dynamical
behavior of such traffic networks rely on monotonicity of the underlying
dynamics. In road traffic modeling, a common model for diverging junctions is
based on the First-in, first-out principle. These type of junctions pose a
problem in the analysis of traffic dynamics, since their dynamics are not
monotone with respect to the positive orthant. However, this technical note
demonstrates that they are in fact monotone with respect to the partial order
induced by a particular, polyhedral cone.
