Modeling Seepage Behavior of Smaller Vehicles in Mixed Traffic Conditions Using an Agent Based Simulation

Abstract

Seepage is an important yet rarely modeled or quantified phenomenon in mixed traffic streams. It describes situations where smaller vehicles do not line up but rather ``seep'' through a queue of stationary or almost stationary vehicles. This contribution introduces seepage into an agent-based transport simulation model. In order to allow vehicles to seep, the traditional first-in-first-out queue model is modified such that in the free flow regime, faster vehicles can overtake slower vehicles and in the congested regime, slower vehicles can overtake faster vehicles. The model is validated with the help of fundamental diagrams. Its sensitivity is investigated by comparing the impact of different shares of smaller vehicles on the speed-density relation in the mixed traffic streams. A case study of the evacuation of Patna, India under mixed traffic conditions with seepage demonstrates the overall approach.