Traffic flow stochastic model (2*2) with discrete set of states and   continuous time
  The present paper proposes a stochastic model of the traffic flow. This model has a discrete set of states and the continuous time. The model is a generalization of the discrete stochastis model that has been considered in a previous paper of this authors collective, for the case of a mixed traffic flow which consists of "fast" and "slow" vehicles. Moreover the continuous time model allows to developed the manner for estimation of characteristics of the traffic flow. 
A. P. Buslaev, A. G. Tatashev, M. V. Yashina