- Email: [email protected]
Freeway Traffic Management Strategy Expert Systems
Copyright © IFAC Transportation Systems. Tianjin. PRC. 1994
FREEWAY TRAFFIC MANAGEMENT STRATEGY EXPERT SYSTEMS Edmond Chin-Ping Chan&, Ph.D., P.E.* and K. K. Ho** • Texas Transponmion Institute, Texas A&:M University System, College Stmion, Texas 77843·3135 USA •• China Engineering Consultants, Inc (CECI), 27FL, 185, Hsin·Hai Rd, Sec. 2, Taipe~ Taiwan, China
Abstract. Significant developments are being made to automate computerized traffic control and management systems along with freeway and expressway system construction in Taiwan, China. Traffic control strategies can be improved by using expert systems technologies according to various traffic management objectives. control device types. and facility locations. Key Words. Artificial intelligence; Expert systems; Software development; Transportation control; Advanced Traffic Management Systems.
decision-making rules will enable operating agencies to upgrade traffic response plans in the future. The expert systems, targeted for use on-line, will assist managers in evaluating alternative control strategies, and enable more consistent implementation of large-scale freeway management systems. This paper examines the general process for incident management. The following section describes the overall system configuration, user interface design, operating procedure, and potential system expansion of the microcomputer-based expert system being developed.
1. INTRODUCTION
Taiwan , China is currently developing an advanced, digital communication based traffic management system as part of the The networked traffic management system. successful operation of the overall Surveillance, !::ommunications, and !::ontrol (SC&C) system will rely on accurate and effective incident detection on freeways, interchanges, and tunnel areas. Automatic incident management techniques, based primarily on real-time detector speed measurements, will be used to reduce the impact of unexpected incidents, undesirable congestion, regional mobility loss, and provide necessary motorist information.
2. STUDY BACKGROUND The computerized traffic control applications allow the user to evaluate different strategies prior to committing full fmancial resources for field design and implementation. This process allows more efficient utilization of existing facilities to enable effective traffic management activities. However, the system development involves significant investment in planning, design, hardware acquisition, installation, and maintenance activities (Chang, 1990; Chang and Huarng 1990):
Improved workstation computing and interactive programming techniques can greatly enhance the implementation of traffic management strategies. Among Artificial Intelligence and Expert Systems technologies, "~owledge !!ased Expert Systems" (KBES) is systematic design procedures and programming techniques that can support decision-making for real-time traffic control and reduce operator errors. This study has extracted knowledge rules in the existing response plans, and developed expert systems for real-time, traffic control advisory. This paper summarizes expert system development to support nationwide freeway control and traffic management implementation.
In most instances, the limitations of time, personnel, and cost, together with knowledge acquisition and recognized expertise, preclude quick expert system development. Once the system is developed, the computerized tool allows more efficient analysis of alternative strategies by other users for more costeffective system operations. The development of microcomputer based expert system has many advantages over the conventional programs (Chang, 1989; Ritchie and Prosser, 1991).
System modules, currently available off-line for the 2nd Freeway system, allow engineers from various operating agencies to interface effectively with the development of traffic response plans. The
317
2.1 System Development Operating agencies, including the hbina ~ngineering honsultants (CECI) and Taiwan Area National ~ngineering ~xpressway !!ureau (TANEEB) , Ministry Qf hommunications (MOC) , Taiwan , China , is currently responsible for a series of planningj design / construction projects, developing in sections and stages, as part of overall freeway and expressway network development.
To provide consistent and long-lasting experience on the freeway traffic management system, advanced considerations are made to provide the freeway and arterial control system integration and IVHS system planning/design/implementation/operations. The detailed system design includes developing technical specifications, engineering estimate, construction schedule, cost analysis, and system bidding process.
2.2 Incident Management Process As shown in Fig. 1. "Recent Freeway System
Development," fairly sizable efforts are underway to develop the system wide traffic control and system development strategy, coordinates traffic management issues, and integrate control system design/planning activities. The overall activities include: (1) Detailed Design on 2nd Freeway (388.2km), and No.1 Freeway sections (274km), and (2) System Planning of 12 Cross-IslandjWestern Seashore Expressways, system interchanges to Western Seashore Expressway (340.24km).
Incident management requires basic information and control responses to manage incidents. This process typically requires the analysis of information type, quantity, and quality of data, or the information needed in highway system analysis. The decision-making process uses a step-by-step, automatic analysis which beginning when an alarm goes off, indicating the incident occurrence. Fig. 2. "Incident Management Process" illustrates the decision-making process requires in order to manage specific incidents. The process includes five (5) steps: incident detection, incident confirmation, incident prediction, incident management, and incident response. This particular analysis focuses on different types of control decisions and responses available to operators and field personnel. The entire process has identified the data requirements and information flows for timely decision-making, such as selecting proper responses (Chang, 1990; Cambridge 1990).
UlCID!rT
D['T'tCTIO'
IlICIDEJfT ASS[Ssnr:JT
Recent Freeway System Development in Taiwan.
IlfC IDElIT
nUAGtnu'7
Fig. 1. Recent Freeway System Development. The design work includes the Detailed Design, System Planning, Comparative Analysis for the successful development of the technical specifications, engineering estimate, construction schedule, cost analysis, and needed documentation to support control system bidding process. The project is closely coordinated with the planned/actual freeway and expressway construction activities.
UCIDtaT
RESPOISI
Fig. 2. Incident Management Process.
318
23 Design Considerations
Efforts are made to identify feasible decision-making areas using feasible expert systems techniques. A user-friendly microcomputer program was developed to assist in decision-making. The stand-alone program was written on MS DOS based IBM/XT/AT/386 or Unix compatible workstations. The program includes an input processor, error messages, and help screens. Personnel can assess alternative management strategies associated with different control options.
In most countries, the increasing traffic demand and inadequate infrastructure development has resulted in the common known "traffic congestion." Even in the most congested areas, unused roadway capacity can be found temporarily within some portion of the freeway and expressway network. While the recurrent incident occurs everyday, non-recurrent incidents have become an increasing problem due to accidents, spilled loads, and other unexpected disasters.
3.1 Real-Time Operations The goal of developing the expert system is to re-route the motorists through the shortest alternate path by optimizing available network resources and system traffic control strategies. The realistic design considerations for implementation include:
"Traffic Diversion" is a traffic system control and management strategy designed to utilize all available capacity in the highway network during various incident-related events. Traffic diversion techniques are often designed with pre- determined control plans and implemented through table-lookup techniques. The Expert System approaches offer one potential real-time traffic control measure that can greatly utilize the computerized traffic management systems, and take advantage of available advanced computer technologies. This study has designed an effective traffic management tool that can eventually formulate diversion strategies automatically in real-time based on the Advanced Traffic Management Systems (ATMS) and Intelligent Yehicle/Highway Systems (IVHS) concept.
1. 2. 3. 4. 5.
Real-time and historical data requirement, Ease of user installation and future update, Ease of system calibration, Networkwide operational complexity, and Potentials of future automatic system self-calibration.
As shown in Fig. 3. "Expert System Architecture", a user-friendly, system-optimal, multi-module approach has been designed. The Incident Management Expert System (IMES) design includes graphical user interface, decision-making production rules, and an inference mechanism. The system is developed to improve the traffic control decision-making and real-time responses. (JSC/NASA, 1993).
3. EXPERT SYSTEM DESIGN Significant efforts are being made to develop the computerized traffic control and management systems along with freeway and expressway system construction. Currently, many control strategies are developed with pre-defined response plans and implemented through site-dependent measures. These response plans are usually embedded with decision-making heuristics for operating alternative control strategies with respective traffic management objectives, control device types, and facility locations. The implementation of expert systems technology can provide a considerable amount of savings in time, money, and investigating efforts by many transportation agencies for "selecting" and "trying" alternative traffic analysis techniques. The system will also provide the implementation basis for summarizing existing solution methodologies used The "Expert Systems" by different agencies. development can provide newly added opportunities to allow the application of successful human expertise to selected, repetitive problems through cautious design and well-defmed applications.
Fig. 3. Expert System Architecture. Various modules, developed in stages, will allow engineers to interface system development and upgrades with enhanced user working experience. The proposed methodology, when operational, can provide traffic managers a dynamic and effective 319
expert system. In particular, the system was designed with three unique user-defmable features:
tool to formulate network traffic diversion strategies during the development of the computerized freeway traffic management systems.
1.
3.2 System Architecture IMES provides an intelligent, user-friendly expert system framework by applying several state-of-the-art computer programming techniques (Cambridge, 1990). The prototype expert system includes a graphical user interface, a mouse supporting function, and an expert system processor for computer operation. As shown In Fig. 4. "Program Operating Procedure," the graphical user interface displays were created to illustrate different portions of highway from which users can directly identify target incidents. The expert system serves as a consultant, helping the user make appropriate decisions according to different situations. OP ERATOR COJ SOL!
2.
3.
The decision-making rules are defmed in external text flles so users can easily modify the rules through an editor. The control responses are also specified in external text files so that each agency can provide agency-specific responses. Besides the ecision variables, a user can also additional study variables for site specific requirements.
By defining operating conditions and reVlSmg responses, a user can implement operational requirements without making internal program modifications. The system is a generalized expert system for managing highway incidents. Since there is no specific traffic response plans available, a set of generic control responses was provided. Users can also design their own response messages. IMES will display messages according to user-defined response messages to test the interactions among the proposed control strategies. 4. CONCLUSIONS Surveillance, ~ommunications, and~ontrol
IKIDErT CONfI Rn ATION
nEn
LOGGING
I
STRATEGY
I rTEGR ATED
SELECTIOJ
CO NTROL UECUTIO N
Fig. 4. Program Operating Procedure.
To provide maximum system expandability, built-in flexibility was incorporated during software development. The user can manipulate IMES by modifying existing production rules, changing study variables, and adding new production rules without recompiling IMES. The user can also change display screen menu items using a common word processor. 3.3 Special Features IMES is a realistic implementation of a rule-based expert system. The basic system can be used intuitively through a window-based user interface. To adapt to the various strategies of incident management applied in different areas, IMES, without programming, provides several facilities for a user to change or enhance the knowledge in the
(SC&C) centers are increasingly used to improve urban freeway corridor operations. Freeway incidents occur unexpectedly and often cause undesirable traffic congestion on urban freeways, even where surveillance and control systems are in operation. Incident managment, including automatic incident detection and rapid response, is an important element in an integrated freeway Iraffic Management System (FfMS) that can minimize the flow-reducing conditions. However, effective freeway system management policy is even more important to manage freeway incidents successfully and assemble all incident information for analysis of available traffic management alternatives. Non-recurring incidents may cause unexpected congestion on freeways, even where surveillance, communication, and control (SC&C) systems are in operation. Incident management, an integral component of the freeway control system, is essential where a freeway is operating near, at, or beyond physical capacity. Engineers, who are bound by physical constraints, traffic characteristics and control practices, must often make decisions on operational effectiveness and trade-off. Off-line computer software is developed to assist control operators in identifying unique conditions and the control strategies needed to determine when and how computerized control systems should respond.
320
This paper presents a microcomputer-based expert system being developed which includes a graphical user interface, decision- making rules, and knowledge inference mechanism that will automate freeway incident management applications. A knowledge- based expert system was developed to assist control operations during incident management, and recommend strategies once incidents have been identified. Efforts were made to summarize, extract, and select the information needed during decision-making so that engineers can implement management techniques. A unified expert system development is made to facilitate the system implementation procedures. The system has translated an expert system using conventional languages for maximum system portability that can automate decision-making for identifying and recommending solutions and automate on-line, real-time responses and management strategies. 5. REFERENCES Chang, Edmond C(1989). "Expert Systems Applications on Freeway Incident Management; Conference Proceeding. "Applications of the Advanced Technologies in Transportation Engineering; American Society of Civil Engineers, Transportation Research Board, San Diego, California, February.
BIOGRAPHY Dr. Edmond Chin-Ping Chang, Ph.D., P.E. is an Associate Research Engineer of the Transport Operations Program of the Texas Transportation Institute at the Texas A&M University System. Dr. Chang has over 17 years of combined Traffic Engineering, Transportation Management, and System Engineering experience, and over 264 publications. Dr. Chang's professional interests include: Computerized Freeway and Arterial Traffic Management Systems, Arterial and Network Signal Timing Optimization, Urban Transportation Systems Analysis, Traffic Flow Theory, Real-Time Traffic Simulation, Microcomputer Applications, Expert Systems, and Artificial Intelligence applications. Mr. K. K. Ho is an Deputy Chief Engineer and Manager of the Computer Center at the China Engineering Consultants, Inc. (CECI) . Besides being responsible for the overall Taipei City Traffic Signal System Manager project, Mr. Ho is currently in charge of the integration of computerized freeway traffic control systems. His working experience includes Management Information System (MIS), computer graphics, computer aided highway design, traffic signal control system, Geographical Information System (GIS), and Database (DB) application planning studies.
Chang, Edmond C(1990). "Development of Expert Systems for Freeway Incident Management - Literature Review." Texas Transportation Institute Research Report 1188-2, February 1990. Chang, Edmond C and Kunhuang Huamg (1990). "Development of Expert Systems for Freeway Incident Management - Microcomputer User's Manual." Texas Transportation Institute Research Report 1188-3, February. (1993). "CLIPS Reference Manual, Version 6.0 of CLIPS." Artificial Intelligence Section, Lyndon B. Johnson Space Center, September. (1990). "Incident Management." Final Report, Prepared for Trucking Research Institute, ATA Foundation, Inc. Cambridge Systems, Inc., October. Ritchie, Stephen G., and Neil A. Prosser (1991). "A Real-Time Expert System Approach To Freeway Incident Management." 1991 Annual Meeting of the Transportation Board, Paper No. 910410, Washington, D.C., January.
321
FREEWAY TRAFFIC MANAGEMENT STRATEGY EXPERT SYSTEMS Edmond Chin-Ping Chan&, Ph.D., P.E.* and K. K. Ho** • Texas Transponmion Institute, Texas A&:M University System, College Stmion, Texas 77843·3135 USA •• China Engineering Consultants, Inc (CECI), 27FL, 185, Hsin·Hai Rd, Sec. 2, Taipe~ Taiwan, China
Abstract. Significant developments are being made to automate computerized traffic control and management systems along with freeway and expressway system construction in Taiwan, China. Traffic control strategies can be improved by using expert systems technologies according to various traffic management objectives. control device types. and facility locations. Key Words. Artificial intelligence; Expert systems; Software development; Transportation control; Advanced Traffic Management Systems.
decision-making rules will enable operating agencies to upgrade traffic response plans in the future. The expert systems, targeted for use on-line, will assist managers in evaluating alternative control strategies, and enable more consistent implementation of large-scale freeway management systems. This paper examines the general process for incident management. The following section describes the overall system configuration, user interface design, operating procedure, and potential system expansion of the microcomputer-based expert system being developed.
1. INTRODUCTION
Taiwan , China is currently developing an advanced, digital communication based traffic management system as part of the The networked traffic management system. successful operation of the overall Surveillance, !::ommunications, and !::ontrol (SC&C) system will rely on accurate and effective incident detection on freeways, interchanges, and tunnel areas. Automatic incident management techniques, based primarily on real-time detector speed measurements, will be used to reduce the impact of unexpected incidents, undesirable congestion, regional mobility loss, and provide necessary motorist information.
2. STUDY BACKGROUND The computerized traffic control applications allow the user to evaluate different strategies prior to committing full fmancial resources for field design and implementation. This process allows more efficient utilization of existing facilities to enable effective traffic management activities. However, the system development involves significant investment in planning, design, hardware acquisition, installation, and maintenance activities (Chang, 1990; Chang and Huarng 1990):
Improved workstation computing and interactive programming techniques can greatly enhance the implementation of traffic management strategies. Among Artificial Intelligence and Expert Systems technologies, "~owledge !!ased Expert Systems" (KBES) is systematic design procedures and programming techniques that can support decision-making for real-time traffic control and reduce operator errors. This study has extracted knowledge rules in the existing response plans, and developed expert systems for real-time, traffic control advisory. This paper summarizes expert system development to support nationwide freeway control and traffic management implementation.
In most instances, the limitations of time, personnel, and cost, together with knowledge acquisition and recognized expertise, preclude quick expert system development. Once the system is developed, the computerized tool allows more efficient analysis of alternative strategies by other users for more costeffective system operations. The development of microcomputer based expert system has many advantages over the conventional programs (Chang, 1989; Ritchie and Prosser, 1991).
System modules, currently available off-line for the 2nd Freeway system, allow engineers from various operating agencies to interface effectively with the development of traffic response plans. The
317
2.1 System Development Operating agencies, including the hbina ~ngineering honsultants (CECI) and Taiwan Area National ~ngineering ~xpressway !!ureau (TANEEB) , Ministry Qf hommunications (MOC) , Taiwan , China , is currently responsible for a series of planningj design / construction projects, developing in sections and stages, as part of overall freeway and expressway network development.
To provide consistent and long-lasting experience on the freeway traffic management system, advanced considerations are made to provide the freeway and arterial control system integration and IVHS system planning/design/implementation/operations. The detailed system design includes developing technical specifications, engineering estimate, construction schedule, cost analysis, and system bidding process.
2.2 Incident Management Process As shown in Fig. 1. "Recent Freeway System
Development," fairly sizable efforts are underway to develop the system wide traffic control and system development strategy, coordinates traffic management issues, and integrate control system design/planning activities. The overall activities include: (1) Detailed Design on 2nd Freeway (388.2km), and No.1 Freeway sections (274km), and (2) System Planning of 12 Cross-IslandjWestern Seashore Expressways, system interchanges to Western Seashore Expressway (340.24km).
Incident management requires basic information and control responses to manage incidents. This process typically requires the analysis of information type, quantity, and quality of data, or the information needed in highway system analysis. The decision-making process uses a step-by-step, automatic analysis which beginning when an alarm goes off, indicating the incident occurrence. Fig. 2. "Incident Management Process" illustrates the decision-making process requires in order to manage specific incidents. The process includes five (5) steps: incident detection, incident confirmation, incident prediction, incident management, and incident response. This particular analysis focuses on different types of control decisions and responses available to operators and field personnel. The entire process has identified the data requirements and information flows for timely decision-making, such as selecting proper responses (Chang, 1990; Cambridge 1990).
UlCID!rT
D['T'tCTIO'
IlICIDEJfT ASS[Ssnr:JT
Recent Freeway System Development in Taiwan.
IlfC IDElIT
nUAGtnu'7
Fig. 1. Recent Freeway System Development. The design work includes the Detailed Design, System Planning, Comparative Analysis for the successful development of the technical specifications, engineering estimate, construction schedule, cost analysis, and needed documentation to support control system bidding process. The project is closely coordinated with the planned/actual freeway and expressway construction activities.
UCIDtaT
RESPOISI
Fig. 2. Incident Management Process.
318
23 Design Considerations
Efforts are made to identify feasible decision-making areas using feasible expert systems techniques. A user-friendly microcomputer program was developed to assist in decision-making. The stand-alone program was written on MS DOS based IBM/XT/AT/386 or Unix compatible workstations. The program includes an input processor, error messages, and help screens. Personnel can assess alternative management strategies associated with different control options.
In most countries, the increasing traffic demand and inadequate infrastructure development has resulted in the common known "traffic congestion." Even in the most congested areas, unused roadway capacity can be found temporarily within some portion of the freeway and expressway network. While the recurrent incident occurs everyday, non-recurrent incidents have become an increasing problem due to accidents, spilled loads, and other unexpected disasters.
3.1 Real-Time Operations The goal of developing the expert system is to re-route the motorists through the shortest alternate path by optimizing available network resources and system traffic control strategies. The realistic design considerations for implementation include:
"Traffic Diversion" is a traffic system control and management strategy designed to utilize all available capacity in the highway network during various incident-related events. Traffic diversion techniques are often designed with pre- determined control plans and implemented through table-lookup techniques. The Expert System approaches offer one potential real-time traffic control measure that can greatly utilize the computerized traffic management systems, and take advantage of available advanced computer technologies. This study has designed an effective traffic management tool that can eventually formulate diversion strategies automatically in real-time based on the Advanced Traffic Management Systems (ATMS) and Intelligent Yehicle/Highway Systems (IVHS) concept.
1. 2. 3. 4. 5.
Real-time and historical data requirement, Ease of user installation and future update, Ease of system calibration, Networkwide operational complexity, and Potentials of future automatic system self-calibration.
As shown in Fig. 3. "Expert System Architecture", a user-friendly, system-optimal, multi-module approach has been designed. The Incident Management Expert System (IMES) design includes graphical user interface, decision-making production rules, and an inference mechanism. The system is developed to improve the traffic control decision-making and real-time responses. (JSC/NASA, 1993).
3. EXPERT SYSTEM DESIGN Significant efforts are being made to develop the computerized traffic control and management systems along with freeway and expressway system construction. Currently, many control strategies are developed with pre-defined response plans and implemented through site-dependent measures. These response plans are usually embedded with decision-making heuristics for operating alternative control strategies with respective traffic management objectives, control device types, and facility locations. The implementation of expert systems technology can provide a considerable amount of savings in time, money, and investigating efforts by many transportation agencies for "selecting" and "trying" alternative traffic analysis techniques. The system will also provide the implementation basis for summarizing existing solution methodologies used The "Expert Systems" by different agencies. development can provide newly added opportunities to allow the application of successful human expertise to selected, repetitive problems through cautious design and well-defmed applications.
Fig. 3. Expert System Architecture. Various modules, developed in stages, will allow engineers to interface system development and upgrades with enhanced user working experience. The proposed methodology, when operational, can provide traffic managers a dynamic and effective 319
expert system. In particular, the system was designed with three unique user-defmable features:
tool to formulate network traffic diversion strategies during the development of the computerized freeway traffic management systems.
1.
3.2 System Architecture IMES provides an intelligent, user-friendly expert system framework by applying several state-of-the-art computer programming techniques (Cambridge, 1990). The prototype expert system includes a graphical user interface, a mouse supporting function, and an expert system processor for computer operation. As shown In Fig. 4. "Program Operating Procedure," the graphical user interface displays were created to illustrate different portions of highway from which users can directly identify target incidents. The expert system serves as a consultant, helping the user make appropriate decisions according to different situations. OP ERATOR COJ SOL!
2.
3.
The decision-making rules are defmed in external text flles so users can easily modify the rules through an editor. The control responses are also specified in external text files so that each agency can provide agency-specific responses. Besides the ecision variables, a user can also additional study variables for site specific requirements.
By defining operating conditions and reVlSmg responses, a user can implement operational requirements without making internal program modifications. The system is a generalized expert system for managing highway incidents. Since there is no specific traffic response plans available, a set of generic control responses was provided. Users can also design their own response messages. IMES will display messages according to user-defined response messages to test the interactions among the proposed control strategies. 4. CONCLUSIONS Surveillance, ~ommunications, and~ontrol
IKIDErT CONfI Rn ATION
nEn
LOGGING
I
STRATEGY
I rTEGR ATED
SELECTIOJ
CO NTROL UECUTIO N
Fig. 4. Program Operating Procedure.
To provide maximum system expandability, built-in flexibility was incorporated during software development. The user can manipulate IMES by modifying existing production rules, changing study variables, and adding new production rules without recompiling IMES. The user can also change display screen menu items using a common word processor. 3.3 Special Features IMES is a realistic implementation of a rule-based expert system. The basic system can be used intuitively through a window-based user interface. To adapt to the various strategies of incident management applied in different areas, IMES, without programming, provides several facilities for a user to change or enhance the knowledge in the
(SC&C) centers are increasingly used to improve urban freeway corridor operations. Freeway incidents occur unexpectedly and often cause undesirable traffic congestion on urban freeways, even where surveillance and control systems are in operation. Incident managment, including automatic incident detection and rapid response, is an important element in an integrated freeway Iraffic Management System (FfMS) that can minimize the flow-reducing conditions. However, effective freeway system management policy is even more important to manage freeway incidents successfully and assemble all incident information for analysis of available traffic management alternatives. Non-recurring incidents may cause unexpected congestion on freeways, even where surveillance, communication, and control (SC&C) systems are in operation. Incident management, an integral component of the freeway control system, is essential where a freeway is operating near, at, or beyond physical capacity. Engineers, who are bound by physical constraints, traffic characteristics and control practices, must often make decisions on operational effectiveness and trade-off. Off-line computer software is developed to assist control operators in identifying unique conditions and the control strategies needed to determine when and how computerized control systems should respond.
320
This paper presents a microcomputer-based expert system being developed which includes a graphical user interface, decision- making rules, and knowledge inference mechanism that will automate freeway incident management applications. A knowledge- based expert system was developed to assist control operations during incident management, and recommend strategies once incidents have been identified. Efforts were made to summarize, extract, and select the information needed during decision-making so that engineers can implement management techniques. A unified expert system development is made to facilitate the system implementation procedures. The system has translated an expert system using conventional languages for maximum system portability that can automate decision-making for identifying and recommending solutions and automate on-line, real-time responses and management strategies. 5. REFERENCES Chang, Edmond C(1989). "Expert Systems Applications on Freeway Incident Management; Conference Proceeding. "Applications of the Advanced Technologies in Transportation Engineering; American Society of Civil Engineers, Transportation Research Board, San Diego, California, February.
BIOGRAPHY Dr. Edmond Chin-Ping Chang, Ph.D., P.E. is an Associate Research Engineer of the Transport Operations Program of the Texas Transportation Institute at the Texas A&M University System. Dr. Chang has over 17 years of combined Traffic Engineering, Transportation Management, and System Engineering experience, and over 264 publications. Dr. Chang's professional interests include: Computerized Freeway and Arterial Traffic Management Systems, Arterial and Network Signal Timing Optimization, Urban Transportation Systems Analysis, Traffic Flow Theory, Real-Time Traffic Simulation, Microcomputer Applications, Expert Systems, and Artificial Intelligence applications. Mr. K. K. Ho is an Deputy Chief Engineer and Manager of the Computer Center at the China Engineering Consultants, Inc. (CECI) . Besides being responsible for the overall Taipei City Traffic Signal System Manager project, Mr. Ho is currently in charge of the integration of computerized freeway traffic control systems. His working experience includes Management Information System (MIS), computer graphics, computer aided highway design, traffic signal control system, Geographical Information System (GIS), and Database (DB) application planning studies.
Chang, Edmond C(1990). "Development of Expert Systems for Freeway Incident Management - Literature Review." Texas Transportation Institute Research Report 1188-2, February 1990. Chang, Edmond C and Kunhuang Huamg (1990). "Development of Expert Systems for Freeway Incident Management - Microcomputer User's Manual." Texas Transportation Institute Research Report 1188-3, February. (1993). "CLIPS Reference Manual, Version 6.0 of CLIPS." Artificial Intelligence Section, Lyndon B. Johnson Space Center, September. (1990). "Incident Management." Final Report, Prepared for Trucking Research Institute, ATA Foundation, Inc. Cambridge Systems, Inc., October. Ritchie, Stephen G., and Neil A. Prosser (1991). "A Real-Time Expert System Approach To Freeway Incident Management." 1991 Annual Meeting of the Transportation Board, Paper No. 910410, Washington, D.C., January.
321