Guidelines for Transportation Management Systems
Transportation Management Systems (TMS) are complex, integrated amalgamations of hardware, technologies, and processes for performing an array of functions, including data acquisition, command and control, computing, and communications. Disruptions or failures in the performance of these functions can impact traffic safety, reduce system capacity, and ultimately lead the traveling public to lose faith in the transportation network. System failures also have the potential to cause measurable economic loss and increase congestion, fuel consumption, pollutants, and traffic crashes. The problem is further complicated by the fact that today's systems, subsystems, and components often are highly interdependent, meaning that a single malfunction can critically impact the ability of the overall systems to perform their intended functions.
System maintenance refers to a series of methodical, ongoing activities designed to minimize the occurrence of systemic failures and to mitigate their impacts when failures do occur. These activities include replacing worn components, installing updated hardware and software, tuning the systems, and anticipating and correcting potential problems and deficiencies. Maintenance includes the development and implementation of action plans for responding quickly, efficiently, and orderly to systemic failures. It also includes an infrastructure and procedures for measuring and monitoring maintenance activities.
In real-world settings, TMS failures will, of course, occur. Consequently, transportation Agencies must plan for and respond to these expected failures. This requires the Agencies to anticipate and furnish the resources, capabilities, and services necessary to maintain the systems throughout their productive lives.
Maintenance plans should be tailored to the technologies comprising the TMS and to the level of maintenance support the Agency is capable of providing. Indeed, it is important the level of maintenance that an Agency can support be integrated from the outset into the planning process and design of the system.
This document offers technical guidance to practitioners on (1) defining a system's maintenance concept, (2) determining the elements to include in the concept, and (3) integrating the maintenance concept into all phases of the system life-cycle.
Currently available documents on TMS maintenance tend to focus on day-to-day issues or on specific maintenance tasks. These documents have not provided detailed information that could guide practitioners on how to systematically integrate maintenance into their program planning, resource allocation, policies, system planning and design, and other related activities that occur throughout the TMS life-cycle. This document provides this guidance and identifies:
Examples of the sorts of concrete practitioner queries answered by this document include the following:
This document is to be used as a technical reference manual — a resource document that provides an overview of the institutional and technical issues associated with the maintenance of a TMS. It will provide the user with a better understanding of the considerations required to develop a multi-year maintenance program for TMS. For many of the technical issues, excellent reference materials exist that provide detailed information, in more of a "how-to" format. These materials are referenced throughout the document.
This document summarizes, at a high level, the problems, challenges, and barriers that Agencies are facing. These barriers include lack of commitment, shortage of resources, and dearth of knowledge regarding tools and techniques for securing and allocating scarce maintenance resources throughout the TMS life-cycle.
The practice and procedures related to capital expenditures for TMS construction and implementation have been standardized around the Federal rules and regulations regarding transportation funding. This is because of the very large role that Federal funding takes in capital spending for transportation. Until recently, however, Federal funding for operations and maintenance has been a relatively small proportion of the total expenditures. One consequence of this low-level Federal involvement in operations and maintenance (O&M) has been a lack of standardized approaches to performing and funding O&M activities. A 1997 National Cooperative Highway Research Program (NCHRP) study that addressed O&M issues received organizational charts from 42 Agencies outlining each Agency structure. No two organizations were alike.
Widely cited research in this area includes the following:
This report builds on the research and recommendations developed in the referenced materials. Detailed examples are provided, as appropriate, as well as specific references to supporting documentation from the literature research.
This document is targeted at Federal, State, and local practitioners involved in the implementation, operation, or maintenance of a TMS. The intended audience includes public and private stakeholders with direct or indirect TMS involvement. The managers, supervisors, engineers, planners, technicians, etc. involved in the development and operation of a TMS will find guidance and recommendations in this document for maintaining the system.
This document is also intended to provide information to those practitioners developing a maintenance plan. It builds on the experiences of maintenance organizations that have had to keep equipment operating without benefit of standard guidelines document or operating procedures.
In this document, use of the term "Transportation Management System (TMS)" refers to an integrated system that includes the Transportation Management Center (TMC), the computer and other automated components, field devices and other peripherals, and the communications infrastructure. The term "TMC" will be used only when discussing the center and/or its contents.
Other terms will be standardized, primarily as an attempt to bring consistency to the practice of TMS maintenance, but, secondarily, to simplify the reading of this document. Take, for example, the term "maintenance model." This term means something completely different to at least two States and, in both cases, has crosscutting implications for development of a maintenance program.
In Arizona, a 1998 report (Ref. 1) documented the Arizona DOT's enhancement of its Performance Controlled System (PECOS), a highway maintenance management system, into a tool that could also model the costs associated with the State's intelligent transportation infrastructure (ITI). In this case, the "maintenance model" referred to a model of the costs associated with maintaining and repairing ITI (also known as TMS) elements.
In contrast, in Oregon, the Western Transportation Institute prepared a very detailed ITS Maintenance Plan in 1999 (Ref. 2). In this report, one of the key issues identified for the Oregon DOT was the need to standardize its "maintenance model" for dealing with ITS elements. In this case, the "model" referred to the sequence of events and procedures for dealing with maintenance (i.e., how system or device failures were reported, who responded, priorities, etc.).
Both of the "maintenance models" described in this example are important parts of developing a maintenance program. Each model, however, describes a different concept. It is, therefore, the practice of this report to discuss technical issues as generically as possible and to minimize the use of terms or jargon that might be misunderstood.
Several key terms used in this report are defined below. Additional terms are presented in the Glossary.
TMC (Transportation Management Center): The building or room where monitoring, command, and control of automated systems, field devices, and/or external information feeds is conducted.
TMS (Transportation Management System): The integrated system that includes the TMC, the computer and other automated components, field devices and other peripherals, and the communications infrastructure.
Maintenance Plan: A documented plan defining a detailed approach to system maintenance. It describes application of the maintenance program to a specific system or set of systems. It typically identifies the maintenance activities, priorities, timetables, and resource commitments and expenditures.
Maintenance Program: Identifies an organization's general approach to system maintenance. It includes the organizational structure and funding support needed to implement the program.
Maintenance Activity: The sequence of actions needed to conduct preventive, periodic, or repair maintenance on a device or subsystem. Typically refers to a specific component (e.g., camera) or subsystem (e.g., computer network).
Operational Concept: Also known as "concept of operations" (or ConOps), it defines the environment in which the TMS will operate. The environment includes the relationship between the system and the Agency's responsibilities, the physical environment, and expectations (performance and life).
Maintenance Concept: Defines the level-of-effort necessary to maintain system availability, reliability, and the functionality necessary to fulfill the operational concept.
Responsive Maintenance: The repair or replacement of failed equipment and its restoration to safe, normal operation. Typically unscheduled, it is in response to an unexpected failure or damage.
Preventive Maintenance: Also called "routine" maintenance, it is the activity performed at regularly scheduled intervals for the upkeep of equipment. Includes checking, testing and inspecting, recordkeeping, cleaning, and periodic replacement when called for in the preventive maintenance schedule.
Emergency Maintenance: Emergency maintenance is similar to responsive maintenance in that it is initiated by a fault or trouble report. However, in this case, the fault is more serious and requires immediate action. Events such as knockdowns, spills, exposed electrical wires, road blockages, etc. are examples of event reports that may require emergency maintenance. Of course, there can also be operational emergencies — e.g., stuck barriers on dedicated HOV lanes or failed lane control signs —that need to be dealt with quickly in order to minimize hazardous circumstances.
This is a resource guide for practitioners in a range of job categories. In most instances, practitioners will not need to read the entire document, but can simply refer to those sections of the report containing materials relevant to their assignments. Table 1-1 identifies representative job titles or descriptions, followed by a list of the chapters or sections associated with the job categories. Study the pertinent chapters or sections. Then use the remainder of the document as a resource guide, which can be consulted as needed.
The remaining chapters in this guide are listed below, along with the major topics discussed in each chapter:
2. Maintenance Considerations & Activities
An overview of what needs to be included in maintenance activities. Several examples are provided along with references to additional detail on key aspects of maintenance.
3. Maintenance Concept & Requirements
Introduction and description of the maintenance concept and how this can be used to develop detailed maintenance requirements. These maintenance requirements can and should be used as part of the design process, but can also be used in other phases of the project life-cycle.
4. Maintenance Considerations for the Life-Cycle of TMC
Expanding on the maintenance concept, how traceability from the operational concept to system performance can be used to continually evaluate maintenance needs.
5. TMC Maintenance Program Guidelines
A listing and discussion of the activities and factors to be considered in the development of a formal maintenance program.
6. TMC Maintenance Program Planning — Multi-Year Considerations
Expanding on the basic guidelines for a maintenance program, there are special considerations for long-term viability and effectiveness of a TMS. This section addresses the life-cycle of a TMS, including system expansion, evolution, and eventual replacement.
7. Maintenance Program Support — Tools & Techniques
Maintenance management and analysis tools to help justify and optimize the allocation of resources. Key performance indicators that can be used to maintain program accountability.