Macroscopic Modeling, Calibration, and Simulation of Managed Lane-Freeway Networks, Part II: Network-scale Calibration and Case Studies

TL;DR

This paper develops a network-scale calibration method for macroscopic models of managed lane-freeway networks, validated through case studies on California freeways, to improve simulation accuracy of complex traffic interactions.

Contribution

It introduces an iterative-learning calibration approach for complex managed lane freeway models, capturing both physical and behavioral traffic phenomena at the network level.

Findings

Successful calibration of freeway parameters using real-world data

Effective modeling of interactions between parallel traffic flows

Validation through case studies on California managed lane freeways

Abstract

In Part I of this paper series, several macroscopic traffic model elements for mathematically describing freeway networks equipped with managed lane facilities were proposed. These modeling techniques seek to capture at the macroscopic the complex phenomena that occur on managed lane-freeway networks, where two parallel traffic flows interact with each other both in the physical sense (how and where cars flow between the two lane groups) and the physiological sense (how driving behaviors are changed by being adjacent to a quantitatively and qualitatively different traffic flow). The local descriptions we developed in Part I are not the only modeling complexity introduced in managed lane-freeway networks. The complex topologies mean that network-scale modeling of a freeway corridor is increased in complexity as well. The already-difficult model calibration problem for a dynamic model of a freeway becomes more complex when the freeway becomes, in effect, two interrelating flow streams. In the present paper, we present an iterative-learning-based approach to calibrating our model's physical and driver-behavioral parameters. We consider the common situation where a complex traffic model needs to be calibrated to recreate real-world baseline traffic behavior, such that counterfactuals can be generated by training purposes. Our method is used to identify traditional freeway parameters as well as the proposed parameters that describe managed lane-freeway-network-specific behaviors. We validate our model and calibration methodology with case studies of simulations of two managed lane-equipped California freeways.