  We investigate the propagation of uncertainties in the Aw-Rascle-Zhang model,
which belongs to a class of second order traffic flow models described by a
system of nonlinear hyperbolic equations. The stochastic quantities are
expanded in terms of wavelet-based series expansions. Then, they are projected
to obtain a deterministic system for the coefficients in the truncated series.
Stochastic Galerkin formulations are presented in conservative form and for
smooth solutions also in the corresponding non-conservative form. This allows
to obtain stabilization results, when the system is relaxed to a first-order
model. Computational tests illustrate the theoretical results.
