Prediction of traffic convective instability with spectral analysis of the Aw–Rascle–Zhang model

•We linearize and diagonalize the ARZ model. We give a Froude number for traffic.•Spectral domain transfer functions are derived and decompose the model.•The linearized system is convectively unstable in the free-flow regime.•We conduct experiments with the linearized model on the NGSIM dataset.•We show that the linearization does not destroy the accuracy of the model.