A Navier-Stokes-like traffic model

In a previous paper (C. Wagner et al., Phys. Rev. E 54 (1996) 5073), we derived a macroscopic traffic model from a Boltzmann-like equation by neglecting third- and higher-order cumulants. To find higher-order approximations, we now employ a Chapman-Enskog expansion to calculate the third-order cumulants. These skewness terms are then expressed in terms of the lower-order cumulants and their derivatives, thus leading to a Navier-Stokes-like model similar to classical hydrodynamics.