Introduction to Network Traffic Flow Theory: Principles, Concepts, Models, and Methods

By Wen-Long Jin

Introduction to Network Traffic Flow Theory: Principles, Concepts, Models, and Methods provides a comprehensive introduction to modern theories for modeling, mathematical analysis and traffic simulations in road networks. The book breaks ground, addressing traffic flow theory in a network setting and providing researchers and transportation professionals with a better understanding of how network traffic flows behave, how congestion builds and dissipates, and how to develop strategies to alleviate network traffic congestion. The book also shows how network traffic flow theory is key to understanding traffic estimation, control, management and planning.

Users wills find this to be a great resource on both theory and applications across a wide swath of subjects, including road networks and reduced traffic congestion.

• Covers the most theoretically and practically relevant network traffic flow theories
• Provides a systematic introduction to traditional and recently developed models, including cell transmission, link transmission, link queue, point queue, macroscopic and microscopic models, junction models and network stationary states
• Applies modern network traffic flow theory to real-world applications in modeling, analysis, estimation, control, management and planning

• Language: English
• Publisher: Elsevier Science
• Release date: Apr 13, 2021
• ISBN: 9780128158418

Wen-Long Jin

Wenlong Jin is an Associate Professor in the Institute of Transportation Studies, at the University of California, Irvine, focusing on the study of drivers' individual choice behaviours (trajectories) and collective queueing processes (cumulative flows). His research interests include modeling and analysing dynamic and stationary traffic patterns at bottlenecks in road networks, using junction models, cell transmission models, link transmission models, capacity drop models, and network stationary models. He has published more than 40 journal articles, including in Elsevier’s Transportation Research Part B: Methodological (for which he serves on the Editorial Advisory Board), and Transportation Research Part C: Emerging Technologies.

Book preview

relation

Part I: Basics

Outline

Introduction

Chapter 1. Introduction

Chapter 2. Definitions of variables

Chapter 3. Basic principles

Chapter 4. Basic concepts

Introduction

The grand aim of all science is to cover the greatest number of empirical facts by logical deduction from the smallest number of hypotheses or axioms. - Albert Einstein

Chapter 1: Introduction

Abstract

Toad transportation systems are designed to move people and goods in space and time. They are inherently complex systems with many stakeholders and conflicting objectives. Essential to transportation system analysis is to understand the interplay between travel demand and supply in a road network. Traffic flow theory aims to study the formation, propagation, and dissipation of traffic congestion subject to different travel demand levels, driving behaviors, and traffic control measures. This book differs from many existing ones on traffic flow theory, as it systematically covers the fundamental principles, concepts, models, and methods for network traffic flow theory. This chapter presents some introductory discussions on transportation system analysis, traffic flow theory, and an overview of the whole book.

Keywords

Transportation system analysis; demand and supply; traffic congestion; network traffic flow theory; principles, concepts, models, and methods

Toad transportation systems are designed to move people and goods in space and time. They are intrinsically complex systems with many stakeholders and conflicting objectives. Essential to transportation system analysis is to understand the interplay between travel demand and supply in a road network. Traffic flow theory aims to study the formation, propagation, and dissipation of traffic congestion subject to different travel demand levels, driving behaviors, and traffic control measures. This book differs from many existing ones on traffic flow theory, as it systematically covers the fundamental principles, concepts, models, and methods for network traffic flow theory. This chapter presents some introductory discussions on transportation system analysis, traffic flow theory, and an overview of the whole book.

1.1 Transportation system analysis

Road transportation systems are critical for the movement of people and goods in space and time. They can be viewed as control systems, as illustrated in Fig. 1.1. Their performance can be measured with respect to safety, comfort, mobility, costs, environmental impacts, land use, equity, livability, and so on. Various control, management, planning, and design strategies have been devised to drive the systems to the desired states, and their performances are constantly monitored with detection, estimation, and communication technologies. In order to design and compare various control measures, transportation engineers need to have a good understanding of how the entire transportation system performs when certain control measures are implemented. Qualitative and quantitative models built on the first principles of various system components and real-world observations can be helpful for these tasks.

Figure 1.1 Transportation systems as control systems.

As illustrated in Fig. 1.2, a transportation system has many stakeholders: general public, including pedestrians and bicyclists, drivers, passengers, goods; fleet operators, including transit agencies and Transportation Network Companies (TNCs), delivery companies; vehicles, including buses, cars, and bikes; car manufacturers; and transportation agencies at the city, state, and federal levels. The performance of a multi-modal transportation system results from the complex interactions among different stakeholders, who usually have different objectives, constraints, characteristics, and choice behaviors. In a transportation system, choice behaviors are hierarchical with social, economic, or engineering categories. In the traditional mobility system served by privately operated vehicles, a driver and a vehicle form a driver-vehicle unit, and the driver makes all the choices related to house locations, jobs, trips, destinations, departure times, modes, routes, lanes, parking, speeds, and so on. In the emerging mobility system with connected, autonomous, electric, and shared vehicles, TNCs and autonomous car manufacturers are the additional stakeholders, and many of the choices are handled by the fleet operators and vehicles themselves.

Figure 1.2 Stakeholders and their choice behaviors in a transportation system.

Many road transportation systems, including freeway and city networks, have been plagued with recurrent and non-recurrent traffic congestion. As illustrated in Fig. 1.3, many locations in the Los Angeles freeway network can be congested from 7:30 to 9:00 in the morning of a typical weekday. Indications of congestion include long queues, slow moving speeds, and high concentration of cars. At the system level, congestion is caused by the imbalance between the supply of capacity provided by the infrastructure and the travel demand of passengers and goods, which are determined by the social and economic choice behaviors in house locations, jobs, trips, destinations, departure times, modes, and routes. A road network can have many bottlenecks, where congestion generally initiates. Since congestion patterns and, therefore, travel delays, are usually location- and time-dependent and stochastic, many transportation control, management, planning, and design problems are quite challenging. Without congestion, many transportation problems would not exist; but congestion is inevitable, since trips tend to be spatially and temporally clustered due to the nature of departure time and other choice behaviors. It has been observed that congestion still occurs after a road expansion, but the length of the peak period could be shorter. In addition, a road expansion or other measures aiming to improve the supply of capacity could induce more cars to the corresponding road. Traffic congestion is a bane of commuters' lives in many metropolitan areas and deteriorates the performance of a transportation system in terms of safety, comfort, mobility, environmental impacts, and social impacts. Therefore, traffic congestion has been a major motivation of the development of transportation planning and engineering strategies with respect to connected and autonomous vehicle technologies, infrastructure management and control, congestion pricing, and public transit and shared