Theory# This section describes the theory and ideas behind POLARIS’ components and provides references to published work. Contents# Demand Model Overview Contents Assignment and Routing Models Routing Multimodal Routing, Assignment, and Simulation Traffic Flow Model Brief Network Description Key parameters applicable to all supported models Further Reading Shared Mobility Supply-Demand Interactions Freight Freight Framework Operations Overview Parking Model Scenario Parameters Electric Vehicle Energy Model Integration with Other Modules Simulation Engine Architecture Overview Discrete-Event Processing Component Managers Multi-Threaded Execution Diagnostics