Advanced Traffic Management Systems Research Articles

Intelligent transportation systems—Enabling technologies

Intelligent transportation programs take many different names throughout the world; in the United States it is ITS, in Europe it is Prometheus, and in Japan it is AMTICS and RACS. All of them share very similar objectives, i.e., the development of advanced Traffic Management Systems, Traveler Information Systems, Vehicle Control Systems, Commercial Vehicle Operations, Public Transportation Systems, and Rural Transportation Systems. Several key technologies stand to serve the synthesis of each and every one of these objectives. These technologies are: Digital Maps, Computers, Path Planning, Human Factors, Sensors, Communications, Vehicle Control, and Traffic Control. This paper discusses each one of these subjects in enough detail to provide the reader with an introduction to both the technology and its state-of-the-art. In addition, the paper discusses socio-politico-economic issues associated with the implementation of the various programs. We believe that this highly neglected subject will serve to temper the development and deployment of these programs.

TERMINUS: A KNOWLEDGE-BASED TRAFFIC MANAGEMENT SYSTEM

The goal of an Advanced Traffic Management System (ATMS) is to efficiently manage transportation resources in response to dynamic traffic conditions. The utility of an ATMS will greatly depend upon its ability to adaptively respond to traffic demands, patterns and permutations. Traffic management systems have historically been limited to addressing the control of street signal lights. Algorithmic solutions to this problem have proved to be very restrictive, while expert system solutions have only shown valid results with small signal networks. None of these approaches has addressed the need for management of the overall transportation system of surface streets, interstate highways, public transportation, and emergency vehicle coordination. The volume of traffic combined with the number of streets and intersections an operator control station must monitor clearly dictates the need for computer support. The application of knowledge-based systems and neural networks provides an ATMS with the technology requi...

Applications of Petri networks and fuzzy logic to advanced traffic management systems: Kim, Seongho, Ph.D. Polytechnic University, 1994. 155 pp

Applications of Petri networks and fuzzy logic to advanced traffic management systems: Kim, Seongho, Ph.D. Polytechnic University, 1994. 155 pp

An evaluation tool for advanced traffic information and management systems in urban networks

Tools for evaluating traffic networks under information supply are a crucial necessity in view of the ATMS/ATIS systems being proposed and implemented around the world as part of Intelligent Vehicle-Highway Systems of the future. This paper presents an evaluation model that incorporates the driver response to information, the traffic flow behavior, and the resulting changes in the characteristics of network paths, into an integrated simulation framework. The model is based on simulating individual vehicle movements according to macroscopic flow principles, the driver path selection behavior under information being explicitly modelled. Detailed modelling of intersection delays as well as a variety of traffic control options for both freeways and arterials are performed. The path-processing component is designed for efficient application of the framework to large and realistic networks. The model can be effectively used for studying alternative information supply and traffic control strategies under various levels of market penetration of in-vehicle ATIS hardware. The paper also discusses its application to candidate networks.

A DYNAMIC TRAFFIC MODEL SYSTEM FOR ATMS/ATIS OPERATIONS

Successful operation of Advanced Traffic Management Systems (ATMS) and Advanced Traveler Information Systems (ATIS) requires a dynamic traffic model that can operate in real time and reliably predict traffic congestion. We present a dynamic traffic model system that consists of four modules: surveillance, origin-destination, congestion prediction and control strategy generation. The heart of the system is a flexible traffic simulation model. A prototype implementation of the proposed system is briefly described.

Estimating Freeway Demand Patterns and Impact of Uncertainty on Ramp Controls

An important application of advanced technology to transportation engineering involves the development of advanced traffic management systems (ATMS). Any proposed traffic-management action is essentially a forecast that the action will cause certain conditions, and uncertainty concerning traffic demand and/or the values of model parameters will introduce random error between what is expected and what actually occurs. This paper considers in some detail the problem of forecasting whether or not a given set of freeway on-ramp volumes are likely to cause overcapacity mainline demand. A simple model for the distribution of freeway traffic is considered, which leads to a straightforward interpretation of the impact of forecast uncertainty as a reduction in practical mainline capacity. The problem of efficient estimation-of-demand model parameters is then taken up; by embedding the demand model in a Markov-process model of freeway traffic flow, it becomes possible to compare three estimation approaches via Monte Carlo methods. These estimators show noticeable differences in statistical efficiency, which translate into practically significant differences in freeway mainline capacity. This suggests that improvements in traffic management may be possible through substitution of efficient for less-efficient statistical procedures.

Optimal Control of Freeway Corridors

Hierarchical traffic control that adapts to exogenous changes, optimizes system performance, and reduces local disturbances is one of the most effective advanced traffic management system methods for relieving congestion in freeway corridors. Optimal ramp‐metering control lies at the center of such a hierarchical control system. However, current ramp‐metering control strategies are not truly dynamic, are not optimal, or consider only parts of the freeway corridor. This paper presents an optimal ramp‐metering control method to alleviate congestion in the interacting corridor components, including freeway, parallel arterials, and connecting streets. The control formulation employs a continuum traffic‐flow model of the corridor dynamics, and the conjugate gradient method to search for optimal ramp‐metering rates according to the total travel time in the corridor. A test of the optimal metering for a simple one‐ramp segment of a freeway corridor is presented.

Real‐Time Traffic Diversion Model: Conceptual Approach

The development of advanced traffic-management systems as a major component of intelligent vehicle/highway systems is targeted to address the complex problem of urban traffic congestion. The strategy includes real-time diversion of traffic during congestion-causing events, by making efficient use of the available capacities in the highway network. A conceptual framework for executing real-time diversions is presented in this paper. The strategy envisages on-line control and management of traffic through control centers and their surveillance equipment. The approach relies on real-time traffic data to detect incidents and develop rerouting plans to benefit motorists. For this purpose, a model has been developed to estimate traveler destinations from traffic data. The dynamic nature of the problem is captured through a traffic assignment/simulation model, which can predict traffic conditions that would prevail in the alternate routes. A knowledge-based expert system is also proposed to estimate traffic delays, and to evaluate and choose alternate routes. This research is being applied to the northern Virginia urban area as a case study.

Data Representation Using a Standard Data Transfer Specification

In the 1990s, digital maps are being used for a wide variety of applications. In the world of digital road maps, the most notable applications are in the area of theIntelligent Vehicle Highway Systems (IVHS). In the USA IVHS is involved with five basic interrelated applications:(i) Advanced Traffic Management Systems.(ii) Advanced Vehicle Control Systems.(iii) Commercial Vehicle Operations.(iv) Advanced Public Transportation Systems.(v) Advanced Traveller Information Systems.

Human Factors and Advanced Traffic Management Systems

Advanced Traffic Management Systems (ATMS) are those components of Intelligent Vehicle Highway Systems (IVHS) that integrate traffic detection, communication, and control functions to be responsive to dynamic traffic conditions and increase the efficiency of existing traffic networks. ATMS provide the management foundation that will enable and integrate other IVHS components such as Commercial Vehicle Operations, Advanced Traveler Information Systems, Advanced Vehicle Control Systems, and Advanced Public Transportation Systems. This paper defines Advanced Traffic Management Systems. It also describes the functions that may take place within an ATMS-class Traffic Management Center (TMC), a scenario that a future TMC operator may encounter, and some of the human factors issues that must be addressed in the design of an ATMS-class TMC.

Human Factors and Advanced Traveler Information Systems (ATIS)

The nation's motoring public is increasingly burdened by recalcitrant transportation problems, many of them directly attributable to increasing traffic congestion. In response to this, the US. Department of transportation is actively moving on several fronts to address this problem. One of the more promising approaches to relieving congestion is through the design and implementation of new technology in the Intelligent Vehicle/Highway System (IVHS). IVHS is composed of five elements: Advanced Traffic Management Systems (ATMS), Advanced Traveler Information Systems (ATIS), Commercial Vehicle Operations (CVO), Advanced Vehicle Control Systems (AVCS), and Advanced Public Transportation Systems (APTS). This paper will discuss human factors issues associated with ATIS.

Intelligent Vehicle Highway Systems (IVHS): Human Factors Issues in Subsystem Development

Intelligent Vehicle-Highway Systems (IVHS) is a major U.S. Department of Transportation initiative to improve the safety and efficiency of our nation's highways. IVHS includes five related components: Advanced Traffic Management Systems (ATMS); Advanced Traveler Information Systems (ATIS); Commercial Vehicle Operations (CVO); Advanced Vehicle Control Systems (AVCS); and, Advanced Public Transportation Systems (APTS). Although the Federal Highway Administration has initially chosen to address each of these components separately, a number of issues are shared by all components. One critical common element deals with the capabilities of the humans in the system. Appropriate guidelines that consider the needs and capabilities of operators, maintainers, and users will be critical for efficient functioning of each system. Efforts are underway to define and resolve critical human factors issues related to IVHS components. This symposium addresses four of the five more highway related IVHS components. For each of these components, presenters will define the key engineering characteristics, hypothetical scenarios that focus on human-system interfaces, and examples of human factors issues that must be considered in the design of IVHS systems.

Technological responses to urban traffic congestion

This is the second of three articles discussing technological responses to urban traffic congestion.This paper reports on the components of intelligent vehicle highway systems, their present state of development around the world, the benefits of adopting these technologies, and the issues that have to be overcome if their potential is to be achieved. The IVHS categories discussed in this paper include: Advanced Traffic Management Systems; Advanced Traveler Information Systems; Commercial Vehicle Operations; and Advanced Vehicle Control Systems.

Advanced Software Design and Standards for Traffic Signal Control

Improved traffic management and control systems are widely reported to be cost-effective investments. Simply retiming signals can provide significant benefits by reducing vehicle stops, travel times, and fuel consumption. The in­ stallation of advanced traffic management systems (ATMS) can provide even greater savings. However, many hardware and software obstacles have impeded the actual implementation of advanced traffic management systems. The general hardware and software limitations of current traffic signal control technology are reviewed. The impact of these deficiencies is discussed in the context of three example ap­ plications. Based on this discussion, the paper identifies several computing issues that should be addressed in order to reduce the effort involved with integrating existing traffic control devices. Adoption of standard industrial control computing platforms and development of new communication and software engineering models are recommended.

Human Factors in Intelligent Vehicle-Highway Systems: A Look to the Future

To achieve greater mobility and safety in highway travel, the Intelligent Vehicle-Highway System (IVHS) concept links the vehicle, driver, highway, and traffic management team using advanced communications and computer-controlled technology. In the near future we will see considerable change in the basic nature of the driving task and the way traffic is managed in the U.S. These changes are driven by the urgent need to address the serious problems of increased traffic congestion, energy waste, high fatality and injury rates, and environmental pollution. Human factors considerations are critical in the design and operation of IVHS. The driver-vehicle and driver-highway interfaces will be altered and will require optimization. Traffic control centers will perform more complex functions and will need the best possible ergonomic design. Traffic management teams will need to be properly configured and trained to meet effective performance criteria for more demanding work conditions. This paper will discuss IVHS human factors issues from the perspective of the Federal Highway Administration (FHWA). It will also review FHWA's IVHS human factors research and development needs and strategies for the near future. The issues and planned FHWA activities for IVHS human factors will be discussed in terms of four elements: Advanced Traffic Management Systems (ATMS), Advanced Traveler Information Systems (ATIS), Commercial Vehicle Operations (CVO), and Advanced Vehicle Control Systems (AVCS).

Dynamic control and traffic performance in a freeway corridor: a simulation study

This paper describes simulation studies that were conducted to assess the performance of a freeway corridor control system. The system combines an advanced traffic management system with a motorist information system that provides route guidance to individual drivers. It has a hierarchical structure: The corridor level control acts in a supervisory capacity dynamically allocating traffic among alternative corridor facilities, including freeways, frontage roads, and signalized arterials. The local level control then selects control parameters for the individual facilities based on the predicted usage at the corridor level. A user specified performance function is optimized in the process. Both recurrent and nonrecurrent congestion scenarios were simulated using the SCOT model as a test bed. It is shown that, in most cases, significant benefits in performance can be obtained when the system operates as designed.

Smart cars and highways go global

The status of plans and projects for intelligent vehicle-highway systems (IVHS) in Europe, Japan, and the US is examined. The four broad areas covered by IVHS are described. They are advanced traffic management systems. advanced traveler information systems commercial vehicle operations systems, and advanced vehicle control systems. A variety of projects in Europe, Japan, and the US which aim at proving the feasibility and practicality of IVHS are described. Socioeconomic factors then could delay or even arrest the development of IVHS are examined.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An investigation of vehicle dependent aspects of terminal area ATC operation.

Description of a terminal area simulation which permits analysis and synthesis of current and advanced air traffic management system configurations including ground and airborne instrumentation and new and modified aircraft characteristics. Ground elements in the simulation include navigation aids, surveillance radars, communication links, air-route structuring, ATC procedures, airport geometries, and runway handling constraints. Airborne elements include traffic samples with individual aircraft performance and operating characteristics and aircraft navigation equipment. The simulation also contains algorithms for conflict detection, conflict resolution, sequencing and pilot-controller data links.