Narrow Results

Starting from a nonlocal version of a classical kinetic traffic model, we derive a class of second-order macroscopic traffic flow models using appropriate moment closure approaches. Under mild assumptions on the closure, we prove that the resulting macroscopic equations fulfill a set of conditions including hyperbolicity, physically reasonable invariant domains and physically reasonable bounds on the speed with which the waves propagate. Finally, numerical results for various situations are presented, illustrating the analytical findings and comparing kinetic and macroscopic solutions.

We establish pointwise bounds for the Green function and consequent linearized stability for multidimensional planar relaxation shocks of general relaxation systems whose equilibrium model is scalar, under the necessary assumption of spectral stability. Moreover, we obtain nonlinear L² asymptotic behavior/sharp decay rate of perturbed weak shocks of general simultaneously-symmetrizable relaxation systems, under small L¹ ∩ H^[d/2]+3 perturbations with first moment in the normal direction to the front.

We consider a discrete kinetic approximation of the isentropic Euler equations, and establish the local convergence of the solutions of these relaxation systems to those of the hydrodynamic equations in the hyperbolic limit. We rely on modulated entropy methods and cover the time interval in which the latter admits smooth solutions.