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.