Fundamentals of Transportation/Introduction
Transportation moves people and goods from one place to another using a variety of vehicles across different infrastructure systems. It does this using not only technology (namely vehicles, energy, and infrastructure), but also people’s time and eﬀort; producing not only the desired outputs of passenger trips and freight shipments, but also adverse outcomes such as air pollution, noise, congestion, crashes, injuries, and fatalities.
Figure 1 illustrates the inputs, outputs, and outcomes of transportation. In the upper left are traditional inputs (infrastructure including pavements, bridges, etc.), labor required to produce transportation, land consumed by infrastructure, energy inputs, and vehicles). Infrastructure is the traditional preserve of civil engineering, while vehicles are anchored in mechanical engineering. Energy, to the extent it is powering existing vehicles is a mechanical engineering question, but the design of systems to reduce or minimize energy consumption require thinking beyond traditional disciplinary boundaries.
On the top of the ﬁgure are Information, Operations, and Management, and Travelers’ Time and Eﬀort. Transportation systems serve people, and are created by people, both the system owners and operators, who run, manage, and maintain the system and travelers who use it. Travelers’ time depends both on freeﬂow time, which is a product of the infrastructure design and on delay due to congestion, which is an interaction of system capacity and its use. On the upper right side of the ﬁgure are the adverse outcomes of transportation, in particular its negative externalities:
- by polluting, systems consume health and increase morbidity and mortality;
- by being dangerous, they consume safety and produce injuries and fatalities;
- by being loud they consume quiet and produce noise (decreasing quality of life and property values); and
- by emitting carbon and other pollutants, they harm the environment.
All of these factors are increasingly being recognized as costs of transportation, but the most notable are the environmental eﬀects, particularly with concerns about global climate change. The bottom of the ﬁgure shows the outputs of transportation. Transportation is central to economic activity and to people’s lives, it enables them to engage in work, attend school, shop for food and other goods, and participate in all of the activities that comprise human existence. More transportation, by increasing accessibility to more destinations, enables people to better meet their personal objectives, but entails higher costs both individually and socially. While the “transportation problem” is often posed in terms of congestion, that delay is but one cost of a system that has many costs and even more benefits. Further, by changing accessibility, transportation gives shape to the development of land.
Modalism and Intermodalism
Transportation is often divided into infrastructure modes: e.g. highway, rail, water, pipeline and air. These can be further divided. Highways include different vehicle types: cars, buses, trucks, motorcycles, bicycles, and pedestrians. Transportation can be further separated into freight and passenger, and urban and inter-city. Passenger transportation is divided in public (or mass) transit (bus, rail, commercial air) and private transportation (car, taxi, general aviation).
These modes of course intersect and interconnect. At-grade crossings of railroads and highways, inter-modal transfer facilities (ports, airports, terminals, stations).
Different combinations of modes are often used on the same trip. I may walk to my car, drive to a parking lot, walk to a shuttle bus, ride the shuttle bus to a stop near my building, and walk into the building where I take an elevator.
Transportation is usually considered to be between buildings (or from one address to another), although many of the same concepts apply within buildings. The operations of an elevator and bus have a lot in common, as do a forklift in a warehouse and a crane at a port.
Transportation engineering is usually taken by undergraduate Civil Engineering students. Not all aim to become transportation professionals, though some do. Loosely, students in this course may consider themselves in one of two categories: Students who intend to specialize in transportation (or are considering it), and students who don't. The remainder of civil engineering often divides into two groups: "Wet" and "Dry". Wets include those studying water resources, hydrology, and environmental engineering, Drys are those involved in structures and geotechnical engineering.
Transportation students have an obvious motivation in the course above and beyond the fact that it is required for graduation. Transportation Engineering is a pre-requisite to further study of Highway Design, Traffic Engineering, Transportation Policy and Planning, and Transportation Materials. It is our hope, that by the end of the semester, many of you will consider yourselves Transportation Students. However not all will.
I am studying Environmental Engineering or Water Resources, why should I care about Transportation Engineering?
Transportation systems have major environmental impacts (air, land, water), both in their construction and utilization. By understanding how transportation systems are designed and operate, those impacts can be measured, managed, and mitigated.
I am studying Structures or Geomechanics, why should I care about Transportation Engineering?
Transportation systems are huge structures of themselves, with very specialized needs and constraints. Only by understanding the systems can the structures (bridges, footings, pavements) be properly designed. Vehicle traffic is the dynamic structural load on these structures.
Citizens and Taxpayers
Everyone participates in society and uses transportation systems. Almost everyone complains about transportation systems. In developed countries you seldom hear similar levels of complaints about water quality or bridges falling down. Why do transportation systems engender such complaints, why do they fail on a daily basis? Are transportation engineers just incompetent? Or is something more fundamental going on?
By understanding the systems as citizens, you can work toward their improvement. Or at least you can entertain your friends at parties.
It is often said that the goal of Transportation Engineering is "The Safe and Efficient Movement of People and Goods."
But that goal (safe and efficient movement of people and goods) doesn’t answer:
Who, What, When, Where, How, Why?
This wikibook is broken into 4 major units
- Transportation Planning: Forecasting, determining needs and standards.
- Transit: Transit demand, service planning, and operations.
- Traffic Engineering (Operations): Queueing, Traffic Flow Highway Capacity and Level of Service (LOS)
- Highway Engineering (Design): Vehicle Performance/Human Factors, Geometric Design
- What constraints keeps us from achieving the goal of transportation systems?
- What is the "Transportation Problem"?
- Identify a transportation problem (local, regional, national, or global) and consider solutions. Research the efficacy of various solutions. Write a one-page memo documenting the problem and solutions, documenting your references.
- LOS - Level of Service
- ITE - Institute of Transportation Engineers
- TRB - Transportation Research Board
- TLA - Three letter abbreviation
- Hierarchy of Roads
- Functional Classification
- Freight, Passenger
- Urban, Intercity
- Public, Private