Interpreting Traffic on a Highway with On/Off Ramps in the Light of TASEP

Abstract

We raise the question whether a simple model for traffic, generic but based on microscopic rules, can provide an additional angle for interpreting flow through a road system. Using the totally simple exclusion process (TASEP) on a road segment with ramps, we show that measuring the flow directly at the road junctions may be a useful setup. We show that the presence of junctions affects the characterisation of traffic, suggesting that interpretations in terms of a 2-phase or a 3-phase description may be complementary, rather than contradictory. We furthermore argue that hysteresis-like features can appear in a system with junctions, which is intriguing as the TASEP dynamics as such do not lead to hysteresis. We discuss our findings in the light of boundary-driven phase transitions.