Slowdown-induced phase transitions in vehicular traffic

Abstract

The occurrence of slowdowns plays a significant role in the flow of traffic. Vehicles that frequently slow down, drop off, and pick up passengers anywhere, often impede the flow of traffic. Using a modified Nagel-Schrekenberg cellular automata model, we analyzed the interplay of road density, random slowdowns, and vehicle speed. We found that increasing random slowdowns beyond a critical value (p_λ ≈ [0.2, 0.3, 0.4] for ρ = [0.20, 0.15, 0.10] respectively) can force a transition from a free flowing traffic into a state where interactions between vehicles reduces the average speed on the road.