Metastable Congested States in Multisegment Traffic Cellular Automaton
  We investigate a simple multisegment cellular automaton model of traffic flow. With the introduction of segment-dependent deceleration probability, metastable congested states in the intermediate density region emerge, and the initial state dependence of the flow is observed. The essential feature of three-phased structure empirically found in real-world traffic flow is reproduced without elaborate assumptions. 
Yutaka Nishimura, Taksu Cheon and Petr Seba