Systems Engineering is primarily a project development process and is performed within the larger context of transportation planning and operations for a region. This section will provide some of the context regarding how systems engineering fits into operations and operations planning.
Operations comprise the activities performed by transportation agencies to achieve the most value from the transportation network, as currently constructed. Operations includes traffic management and a range of other activities, with the goal of maximizing the return on the infrastructure investment. The value of the network is adversely affected principally by congestion, which occurs whenever demand exceeds capacity in some part of the network. Congestion is marked by persistent, residual queueing, which imposes increased delay, interruptions of continuous flow (that may contribute to crashes), unreliable travel times, increased emissions, and reduced quality of life.
Congestion may be inevitable. Increasing demand for movement of people, goods and services is the natural product of increased economic and social activity, which are identified as goals by most state and local governments that manage traffic. Thus, increasing demand is the outcome of desirable trends. Network capacity, on the other hand, is limited, and the ability to increase it is constrained by many factors, some of which are also closely tied to perceptions of the quality of life. Thus, transportation operators are faced with increasing operational challenges in trying to keep congestion at bay. To minimize congestion, operations strategies either seek to increase or optimize capacity, or they seek to manage demand.
Capacity may be increased by expanding the built infrastructure, but doing so incurs a high cost and requires a long-term process of planning to address environmental and societal challenges. But capacity may also be increased by making use of existing infrastructure more efficiently, even in temporary ways. For example, part-time use of shoulders during congested conditions is a strategy for increasing capacity. Adjusting signal timing to favor the congested direction, particularly to serve a larger network need, is also a strategy for increasing capacity.
Many operational activities undertaken by agencies also seek to manage demand. Demand management includes strategies that seek one or more of the following three objectives:
· Spatial diversion, where traffic is encouraged to use an alternate route that avoids congestion in order to minimize the congestion delay faced by most travelers.
· Temporal diversion, where travelers are encouraged to choose a less congested time of day to make their trip.
· Modal diversion, where travelers are encouraged to choose a less congested mode, particularly a high-density mode such as transit.
Transportation agencies and private-sector providers employ a range of tools to empower travelers to seek these alternatives. Modal and temporal diversion, however, affects travelers before they begin their trip, and strategies to attain these objectives are based on providing information to travelers before travel, or at least before relevant portions of their trips. Travelers are empowered to choose different departure times or make decisions based upon additional information—information about current network conditions or information they need to explore alternatives. A substantial and increasing body of technology has and will be implemented to carry out these strategies. Many of these technologies are implemented by private-sector service providers, and focus on information provided directly to travelers on devices they carry with them.
Once the trip has begun, travelers no longer have the option to change departure times or modes, and spatial diversion becomes the principal objective that transportation agencies seek to attain in order to manage congestion. Much traditional operational technology involving ITS field devices carries out these strategies, including such technologies as dynamic message signs, highway advisory radio, lane control signals, and the like. But agencies are expanding their operational strategies to use emerging technologies, including routing services that depend on macroscopic performance data—from agency-owned sensors as well as crowd-sourced—to recommend congestion-avoidance routes.
Clearly, attaining these objectives requires that data-gathering technologies, information technologies, and control technologies integrate fully and meaningfully. It also requires that the agencies who own or are served by these technologies work together at the agency to agency level.
The integration of agency activities and the integration of their technologies are separate challenges. Agency-level integration suggests robust regional planning processes, where all the agencies in a region develop a consensus around their goals, objectives, and strategies. Agencies in a region must:
· Understand the nature of the congestion problem
· Devise and document the operational strategies that might minimize the effects of those problems
· Plan the activities undertaken by each agency to carry out those strategies
· Develop within each agency the capability to reliably undertake those activities (including staffing, facilities, management structures, equipment, administrative and business support, among others)
· Determine the systems and technologies needed to support those strategies
· Develop an implementation plan by which those systems and technologies will be implemented and integrated, formulated as a series of projects
· Carry out that plan with a series of projects, with engineering processes in place that ensure those projects will efficiently attain the objectives driving the plan
Only the last two bullets are project-related. A strong program of ITS projects depends fundamentally on a strong regional operations planning process that first defines what agencies will do as the basis for determining what technologies they need.
Systems engineering is the process by which the operational strategies articulated by an agency become fully and efficiently supported by the technology they build. Stated another way, systems engineering helps agencies ensure that their scarce operational capital funds are spent in a way that most directly serves the attainment of their operational goals and objectives.
Project success is therefore measured by how well the implemented technology supports the needs of the people who use it, as embodied in the activities they undertake to attain their objectives.
Articulating and documenting objectives should flow from a planning process that determines the nature, scope, and basic budget for a project. An understanding of goals is an important input to the deployment of a project to support transportation system operation that contributes to the achievement of those goals. The outputs of the planning process help support program and project development.
Some planning activities are parts of formal planning processes that conform to guidelines required for the expenditure of the Highway Trust Fund. Some are not defined formally in that way, but provide a contextual clarity for operations technology projects that reduces the workload required to develop systems engineering products. Figure 1 shows a representation of this relationship between planning and project focused processes.
Figure 1. The Relationship of the Planning Process to the Systems Engineering Process
(Source: FHWA)
The importance of the planning foundation for ITS projects cannot be overstated. Technology projects support operational activities, and operational activities attain operational objectives, which are drawn from organizational and regional goals. The exact organization of the planning documents shown at the left in Figure 1 is not formally defined, and they can be combined or developed concurrently. No matter how they are developed, however, they are mutually informed to provide a consistent regional picture of operational activities and how integrated ITS supports those activities.
The question of who develops these documents helps clarify what they are about. The Long-Range Transportation Plan, the Congestion Management Plan, short-range and corridor plans, and the Transportation Improvement Program are formal planning documents subject to specific requirements and oversight. These documents are prepared by transportation planners, often in collaboration between metropolitan planning organizations and local agencies, and with support from operations professionals in those agencies. The Operations Plan (whatever it may be called in a region) should primarily be a product of operations professionals in regional agencies, perhaps with support and facilitation from MPOs. The Regional Architecture is a collaboration between transportation planners and operations professionals. Agencies often seek assistance from consultants and contractors for developing these various documents, but they will only be meaningful and useful if they accurately reflect the goals, objectives, and strategies of the transportation agencies in a region. To realize the full value of those documents, agencies must remain fully engaged in their development, and be prepared to own what those documents say.
These planning documents explain and document the why of projects and their basic strategic operational approach, and are developed as a collaboration between planners and agency operations professionals. A project formulated to install dynamic messages signs, for example, might attract the question, “why dynamic message signs instead of, say, smart phone apps?” These questions are best addressed during the planning process.
When that planning support has not been developed, systems
engineering must attempt to fill that vacuum, and Concepts of Operation end up
with extended discussions of planning questions and answers, instead of
focusing on the users of the system being implemented and their specific needs.
The lack of planning puts a burden on the systems engineering process that it
is not designed to bear.
Good supporting planning greatly reduces the effort required for systems engineering, even for complex projects where systems engineering documents will be developed from scratch as part of the project development.
The reader should take from this section simply that systems engineering is a project process that depends on a strong transportation and operational planning foundation.
