First - In - First - Out Properties of a Commodity - based Kinematic Wave Simulation Model

Computational efficiency and First-In-First-Out (FIFO) are both important issues in applications such as dynamic traffic assignment. In this paper, we first show by example the FIFO properties of a computationally efficient commodity-based kinematic wave (CKW) model of network traffic flow. After developing measurements of FIFO violation among commodities in location and time, based on misplacement of vehicles in total and commodity traffic, we theoretically argue that numerical CKW solutions converge to FIFO ones. Then with numerical examples, we show that FIFO violation in CKW solutions is a function of simulation time and number of commodities, but decreases with decreasing cell lengths, even for infinite number of commodities. Finally we discuss possible implications of this study.