Macroscopic simulation of widely scattered synchronized traffic states

Recently, a phase transition to synchronized congested traffic has been observed in empirical highway data [B. S. Kerner and H. Rehborn, Phys. Rev. Lett. 79, 4030 (1997)]. This hysteretic transition has been described by a non-local, gas-kinetic-based traffic model [D. Helbing and M. Treiber, Phys. Rev. Lett. 81, 3042 (1998)] that, however, did not display the wide scattering of synchronized states. Here, it is shown that the latter can be reproduced by a mixture of different vehicle types like cars and trucks. The simulation results are in good agreement with Dutch highway data.