Transportation Asset Management

Methodology and Applications

Zongzhi Li

• Editore: CRC Press
• Anno: 2018
• ISBN:
  9781351644259
• Edizione: 1
• Argomento: Technik & Maschinenbau
• Categoria: Bauingenieurwesen

Transportation asset management delivers efficient and cost-effective investment decisions to support transportation infrastructure and system usage performance measured in economic, social, health, and environmental terms. It can be applied at national, state, and local levels. This distinctive book addresses asset management for multimodal transportation, taking account of system component interdependency, integration, and risk and uncertainty. It sets out rigorous quantitative and qualitative methods for addressing system goals, performance measures, and needs; data collection and management; performance modeling; project evaluation, selection, and trade-off analysis; innovative financing; and institutional issues. It applies as easily to static traffic and time-dependent or dynamic traffic which exists on a more local level.

It is written for transportation planners, engineers, and academia, as well as a growing number of graduate students taking transportation asset management courses.

Chapter 1

Introduction

1.1Overview of a multimodal transportation system

A multimodal transportation system comprises three components: physical transportation facilities, vehicles, and users/nonusers corresponding to passenger travel and freight shipments. The mission of a transportation system is to ensure safe and efficient movements of people and goods, which are predominantly achieved by various types of vehicles. The use of vehicles is constrained by availability of physical transportation facilities that have limited usage capacities. Thus, the three components—facilities, vehicles, and users/nonusers—are interdependent on one another, and should, therefore, be addressed holistically.

1.1.1Multimodal transportation facilities

A transportation system involves various types of physical facilities, such as roads, bridges, drainage structures, tunnels, traffic control devices and safety hardware (signs, lighting, signals, pavement markings, guardrails, and crash cushions), roadside furniture, transit stops and stations, rail tracks, navigable waterway channels and ports, and pipelines. Each facility plays a unique role in providing transportation services. For instance, roads, bridges, drainage structures, and tunnels carry traffic; traffic control devices and safety hardware foster smooth traffic flow and safety; and roadside furniture enhances convenience and aesthetics. For passenger travel or freight shipments, one type of transportation facility may be used by different types of vehicles or multiple types of transportation facilities may be used by one type of vehicle. Facilities used by vehicles for people or goods movements could be largely grouped according to travel modes.

1.1.2Transportation vehicles

For passenger travel, typical travel modes include auto (private, taxi, rideshare), transit (bus and bus rapid transit, streetcar and light rail, subway and commuter rail, ferry), air, non-motorized (bike, e-bike, scooter), and walking modes. Vehicle types may include automobiles, buses, streetcars, light rail vehicles, subway/metro trains, ferryboats, airplanes, bikes, e-bikes, and scooters. For freight shipments, key travel modes include trucking, freight rail, shipping, cargo air, and pipeline modes. Vehicle types generally consist of trucks, freight trains, ships, and cargo planes.

1.1.3Passenger and freight movements

The service provided by a transportation system is generally related to passenger travel and freight shipments. For a given transportation system, the two categories of service occur simultaneously. Ensuring safe and efficient travel of people and shipping of goods from respective origins to destinations are at the core of transportation service.

1.2Transportation system characteristics

1.2.1Interdependent system components

The facility, vehicle, and user/nonuser components that make up a transportation system are interdependent on one another. People and goods are moved by different types of vehicles. The shared facilities used by vehicles have limited capacities. In temporal and spatial dimensions, the travel demand of people and goods for a certain area is assigned to traffic zones and travel modes, and then converted to traffic flow on routes. To provide acceptable levels of service, people travel and goods movements, travel mode, vehicles, and facilities need to be adequately matched. Traffic impacts could be analyzed to assess levels of service. Meanwhile, vehicle usage and facility performance could also be evaluated.

1.2.2System component life cycle considerations

As part of dealing with the interdependent transportation system components (facilities, vehicles, users/nonusers) holistically, the useful service life cycles of system components need to be taken into consideration to ensure they are treated in an equitable manner. This is because different system components have different life cycles. Different types of facilities, vehicles or users/nonusers in the context of each system component also exhibit differences in their service lives. For a specific facility, its delivery process goes through planning, programming, design, construction, and in-service steps. The useful service life cycle is typically defined as the time interval between two consecutive construction interventions. During the service life cycle, repetitive maintenance and repair treatments are implemented in a coordinated manner to ensure the designed service life is achieved. Likewise, for a specific vehicle, the delivery process involves planning, design, manufacturing, and in-service steps. It also maintains a life span from production to retirement and will include repair and maintenance while in service. Although the entire life span of a person or a piece of goods may not be fully associated with the transportation system, the age of the person or the piece of goods does affect the performance of vehicles and, in turn, the performance of facilities. At any certain point in time, people and goods of various ages are using a transportation system. Similarly, a wide range of age distributions of people and goods may pass by one location of a transportation system over a certain period. Moreover, people or goods in the same age group may behave differently. Considering service life cycles of facility, vehicle, and user/nonuser components will help assess their temporal and spatial interdependency, interactions, and performance in a more rigorous manner.

1.2.3Multidimensional impacts and multiple performance goals

With facility, vehicle, and user/nonuser components considered holistically over their respective service life spans, the impacts of the three system components in time and space dimensions are multidimensional in nature. The impacts can be classified into direct and indirect impacts. The direct impacts are directly relevant to the three components of a transportation system in time and space dimensions. The indirect impacts are related to those caused by the transportation system, such as economic growth triggered by transportation improvements. The overarching goals of managing the transportation system are to mitigate adverse impacts and promote positive impacts to achieve efficiency, effectiveness, and equity. For the facility component, specific performance management goals include preserving physical facility conditions at or above a desired level and minimizing transportation agency costs. For vehicle and user/nonuser components that are associated with system usage, the specific performance management goals are concerned with minimizing user/nonuser costs, ensuring certain levels of service for vehicle/user/nonuser mobility and safety, and reducing energy consumption and environmental impacts. The indirect performance management goals are geared toward job creation and freight shipment quantities in support of economic prosperity. The relative importance of various performance management goals among facility, vehicle, and user/nonuser components, and the goals dealing with different types of facilities, vehicles, and users/nonusers for each system component may be treated differently. Also, the relative importance may change over time. Tradeoffs among the goals need to be considered in the process of decision-making.

1.3Transportation asset management process

Transportation asset management can be defined as a strategic, systematic process of constructing, preserving, expanding, and operating the transportation system to achieve a cost-efficient, effective, and equitable system performance. It focuses on engineering and business practices for predicting the travel demand that directly affects the performance of physical facilities and system usage. It may rely on innovative financing to maximize the budget and allocating the available funding to address the needs for performance improvements in a holistic and proactive manner (Li et al., 2002a,b; Li and Sinha, 2004). Figure 1.1 shows key components of the systematic transportation asset management process that generally accomplish the following functions:

•Establish transportation performance management goals and performance measures

•Carry out travel demand and traffic flow predictions

•Conduct transportation facility and system usage performance modeling

•Analyze performance trends according to predicted traffic and non-traffic conditions

•Assess needs for facility and system usage performance improvements, and recommend investment alternatives

•Evaluate the economic feasibility of investment alternatives

•Identify the best sub-collection of economically feasible investment alternatives under budget and other constraints

•Implement selected investment alternatives

•Provide feedback to refine the subsequent cycle decisions

Figure 1.1Framework of transportation asset management.

1.3.1Transportation goals, objectives, and performance measures

A policy goal is a general statement of a desired state or ideal function of a transportation system. A system management goal or an objective is a concrete step toward achieving a policy goal, stated in measurable terms. Goals and objectives reflect the perceptions of the transportation agency and the users of what the transportation system should achieve. The overarching policy goals are transportation efficiency, effectiveness, and equity, which can be stated in a more concrete form as transportation agency and user-related objectives, including facility preservation, agency and user costs, traffic mobility, safety, and environmental impacts, as well as the indirect objective of stimulating economic development. Performance measures are specific quantitative or qualitative indicators that directly or indirectly reflect the extent to which a transportation system stimulus realizes its agency and user objectives. They could provide information on the extent to which the expected facility and operation performance targets are met, the transportation users are satisfied with changes or improvements in the service, and the way in which available resources are transformed into performance improvements from resource allocation.

1.3.2Data needs, collection, processing, and database management

The analyses associated with the key components of transportation asset management, ranging from performance modeling to project selection and programming, are intensively data-driven. Specifically, the historical and current data collected will help monitor the deterioration trend and the current condition of the existing physical facility and system usage performance. Such data can be employed to calibrate statistic...