DYNAMICAL PHASE-TRANSITION IN ONE-DIMENSIONAL TRAFFIC FLOW MODEL WITHBLOCKAGE

Effects of a bottleneck in a linear trafficway is investigated using a simple cellular automation model. Introducing a blockage site which t ransmit cars at some transmission probability into the rule-184 cellul ar automation, we observe three different phases with increasing car c oncentration: Besides the free phase and the jam phase, which exist al ready in the pure rule-184 model, the mixed phase of these two appears at intermediate concentration with well-defined phase boundaries. Thi s mixed phase, where cars pile up behind the blockage to form a jam re gion, is characterized by a constant flow. In the thermodynamic limit, we obtain the exact expressions for several characteristic quantities in terms of the car density and the transmission rate. These quantiti es depend strongly on the system size at the phase boundaries; We anal yse these finite size effects based on the finite-size scaling.