Model Reference Adaptive Control Framework for Real-Time Traffic Management under Emergency Evacuation

Abstract

Recent natural or man-made disasters around the world have provided compelling evidence that transportation system plays a crucial role in the emergency evacuation and have stressed the need for effective evacuation traffic management to maximize the utilization of the transportation system and to minimize fatalities and losses. This paper presents a model reference adaptive control (MRAC) framework for real time traffic management under emergency evacuation.Distinct from the well-studied evacuation planning, real time traffic management for evacuation aims to dynamically guide (control) traffic flow under evacuation in such a way that certain system objective (e.g. minimization of fatalities or property losses) could be achieved. The proposed framework is based on both dynamic network modeling techniques and adaptive control theory, by considering the traffic network under evacuation as a dynamic system. Firstly, a prescriptive dynamic traffic assignment model is applied to predict, in a short-term and rollinghorizon manner, the desired traffic states based on certain system optimal objectives. This model will serve as a reference point for the adaptive control. Then, the adaptive control system integrates these desired states and the current prevailing traffic conditions collected via the sensing system to produce real time traffic control schemes. Finally, these traffic control schemes are implemented in the field to guide the real world traffic flow to evolve towards the desired states. Simulation studies provided in this paper show that the proposed framework based on MRAC can significantly improve the performance of real time evacuation traffic management.

Optimization of a Traffic Control Scheme for a Post-Disaster Urban Road Network

“…As a goal, a multi-objective traffic control scheme model was established based on the theory of bi-level programming methods and network optimization, and a fuzzy interactive algorithm and genetic algorithm were used to find the solution. Liu et al [17] proposed a model reference adaptive control (MRAC) framework to conduct real-time traffic management during a post-disaster emergency evacuation to dynamically control the traffic flow and reduce casualties and property losses. In consideration of the demands of emergency responders after accidents, Konstantinidou et al [18] studied the joint planning problem of emergency evacuation and emergency traffic management.…”

Determining the effective distance of emergency evacuation signs

“…This assumption makes it difficult to capture some important features such as stampeding or blocking. In fact, an individual following the guidance is probabilistic, depending on his/her trust of the guidance and his/her familiarity with the evacuation routes [11]. Therefore, a coefficient a (0rar1) is introduced to reflect the level of an evacuee, which can comply with the EESs.…”

Modeling of Evacuation and Background Traffic for Optimal Zone-Based Vehicle Evacuation Strategy

“…Several evacuation decision models were proposed in the early 1980s and 1990s (12,13). Recent works include models on traffic management strategies and optimal scheduling and traffic assignment decisions (3,14), contraflow planning and network design (15,16), and optimal signal design for evacuation (17).…”