Abstract: This paper studied the Riemann problem for the Aw-Rascle traffic flow model with a composite pressure term. First，using the characteristic analysis method，we calculated the eigenvalues，eigenvectors，and corresponding fundamental wave curves of the AwRascle traffic flow model. Then，using the phase plane analysis method，the correspondingRiemann solutions for all cases were given. Finally，we discussed the limiting behavior of the Riemann solution when the pressure disappeared，and studied the formation of the δ-shock wave and vacuum state during the process of pressure disappearance.

Key words: Aw-Rascle traffic flow, Riemann problem, δ-shock wave, vacuum state, singular limit