Glossary of Transportation Terms
Arterial Highway: Arterial highways serve major traffic movements or major traffic corridors. While they may provide access to abutting land, their primary function is to serve traffic moving through the area.
Average Daily Traffic Volume (ADT): The average number of vehicles that travel on a given road during the day. As defined by traffic engineers, it is the total traffic volume during a given time period in whole days (24-hour periods), greater than one day and less than one year, divided by the number of days in that time period.
Capacity: The maximum number of vehicles that can reasonably be expected to pass over a lane or a roadway during a given time period under prevailing roadway and traffic conditions. Typically, the maximum expressway capacity for automobiles is 2,000 vehicles per lane per hour.
Categorical Exclusion (CE): is prepared for projects that cause minimal social, economic or environmental impact.
Collector Highway: Collector highways are those highways that link local highways to arterial highways.
Collectors: In rural areas, routes serving intra-county, rather than statewide travel. In urban areas, streets providing direct access to neighborhoods as well as direct access to arterial.
Constructability: A detailed review of construction issues and sequencing of a project during the project development phase.
Controlled Access: Partial access restriction that gives preference to through traffic. Also provides for connections to selected public routes and to certain other adjacent locations where vehicles can enter or leave a roadway safely without interfering with through traffic.
Corridor: Land between two termini within which traffic, transit, land use, topography, environment, and other characteristics are evaluated for transportation purposes. Also, it is the general width in which alternative alignments can be located.
Design Criteria: Established state and national standards and procedures that guide the establishment of roadway layouts, alignments, geometry, and dimensions for specified types of roadways in certain defined conditions. The principal design criteria for roadways are traffic volume, design speed, the physical characteristics of vehicles, the classification of vehicles, and the percentage of various vehicle classification types that use the roadway.
Environmental Assessment (EA): is prepared for larger scale projects that do not meet the requirements for CE or those for which the significance of the environmental impact is not clearly established. Should environmental analysis and interagency review during the EA process find a project to have no significant impacts on the quality of the environmental, a Finding of No Significant Impact (FONSI) is issued. If it is found that the project will have significant impacts, an EIS must be prepared.
Environmental Impact Statement (EIS): is prepared for projects that will cause a significant adverse effect on the environment.
Environmental Overview: A beginning or summary assessment of environmental features in a study area, usually performed during systems planning or preliminary environmental activities. From this preliminary information, the environmental impacts of the study alternatives will be determined. This overview may sometimes be referred to as Environmental Screening.
Federal Aid Project: An activity, study, survey, project, or other work related to transportation authorized in advance by the Federal Highway Administration, Federal Transit Administration, or other federal agency, and which is paid for either partially or fully by public funds.
Federal Highway Administration (FHWA): The FHWA deals with highway transportation in its broadest scope, administrating all federal transportation programs, including FLHP.
Federal Lands Highway Program (FLHP): The FLHP funds transportation system investment for transportation facilities providing access to and within National Forests, National parks, National Refuges, Indian Lands, and other public lands. Federal Transit Authority: The FTA funds the development of mass transportation systems such as subway and bus systems.
Finding of No Significant Impact (FONSI): A FONSI is the formal finding that the project will not have significant impact based on the environmental assessment.
Functional Roadway Classification: The organization of roadways into a hierarchy based on the character of service provided. Typical classifications include arterial, local, and collection roadways.
Geographic Information System (GIS): A computer-based system that links the geographic location of map features to text information or databases
Geometric Design: Design that deals with the dimensions of a facility and the relationships of its features such as alignment, profile, grades, widths, sight distances, clearances, and slopes as distinguished from structural design which is concerned with thickness, composition of materials, and load-carrying capacity.
Impacts: Positive or negative effects upon the natural or human environment resulting from transportation projects.
Intelligent Transportation Systems (ITS): Refers to the use of advances technologies (such as traffic sensors and communications equipment) to improve transportation operations.
Intermodal: A mode is a particular form of transportation, such as automobile, transit, carpool, ship and bike. Intermodal refers to connections between modes.
Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA): Federal Legislature that mandated the way transportation decisions were to be made and funded. This landmark $155 billion federal legislation signed into law in December 1991, called for broad changes in transportation decision-making, and included major revisions to metropolitan and statewide planning processes. ISTEA emphasized diversity and balance of modes, as well as the preservation of existing over construction of new facilities. The law expired in September 1997, and was followed by TEA-21.
Level of Service: A rating system used by traffic engineers to determine a roadway ability to provide adequate capacity for the volume of traffic (number of vehicles) using the road.
Limited-Access Highway: A highway that has access to it restricted to designated points such as interchanges.
Major Investment Study (MIS): The MIS is an evaluation of the effectiveness (such as level of use and ability to meet the mobility needs of the public) and cost-effectiveness of alternative transportation investments in attaining local, state, and regional goals and objectives for the metropolitan or rural area. The study uses a cooperative process that leads to a decision on the design concept and fiscal scope of an investment(s). The recommended design concept(s) may result in additional development as a transportation project(s).
Metropolitan Planning Organization (MPO): A planning group designated for each urban area with a population of 50,000 or more. Members include both private citizens and local government officials. An MPO addresses Federal aid planning mandates by producing local area transportation plans or transportation improvement programs on an annual or biannual basis, or by employing other strategies that make existing systems more efficient.
Mitigation Measures: Specific design commitments made during the environmental evaluation and study process that serve to moderate or lessen impacts deriving from the proposed action. These measures may include planning and development commitments, environmental measures, right-of-way improvements, and agreements with resource or other agencies to effect construction or post construction action.
National Environmental Policy Act (NEPA): The United States Congress enacted the National Environmental Policy Act of 1969 (NEPA) to establish a national policy to protect the environmental. The act is codified in Title 42 of the United States Code, Sections 4321 through 4347 (abbreviated as 42 USC 4321-4347). On January 1, 1970, NEPA was signed into law by President Richard Nixon.
No-Build Alternative (also known as “No-Action Alternative”): Option of maintaining the status quo by not building transportation improvements. Serves as a baseline for comparison of “Build” Alternatives.
Park and Ride: A transportation option whereby commuters park their cars in designated lots and complete their trips using public transportation or joining other commuters in a high-occupancy vehicle (HOV) (e.g., buses, subways, and carpool/vanpool).
Phase I Design: Early phases of technical studies undertaken to determine all relevant aspects of transportation location, to identify feasible route alternatives or design options, and to assess various cost and benefit parameters before advancing the project into more. Detailed final design development.
Phase II Design: Detailed roadway design along a specific alignment. This phase includes completion Right-of-Way and Construction plans. Environmental commitments are incorporated into the plans during the phase.
Photo Renderings: Visual illustrations of projects in development developed by scanning the desired photographic view and directly superimposing a computer-generated model of the project. These may consist of 2-dimensional computer generated renderings, 2-dimensional photographic overlays and enhancements, 3-dimensional photographic overlays and enhancements, or 3-dimaensional computer generated renderings.
Prime Farmland: Land that has the best combination of physical and chemical characteristics for producing food, feed, fiber, forage oil, seed, and other agricultural crops with minimum inputs of fuel, fertilizer, pesticides, and labor and without intolerable soil erosion, as determined by the Secretary of Agriculture. It does not include land that is already committed to urban development or storage.
Programming: A general term to refer to a series of activities carried out by planners, including data assessment, appraisal of identified planning needs, and consideration of available or anticipated fiscal resources to result in the drawing up, scheduling, and planning of a list of identified transportation improvements for a given period of time.
Public Hearing: A NEPA required meeting designed to afford the public the latest project information and the opportunity to express support of or opposition to a transportation project in an forum at which a verbatim record (transcript) of the proceedings is kept.
Public Meeting: An announced meeting conducted by transportation officials designed to facilitate participation in the decision-making process and to assist the public in gaining an informed view of a proposed project at any level of the transportation project development process. Also, such a gathering may be referred to as a public information meeting.
State-Funded Project: The design or construction of an improvement that is funded entirely with state highway or bridge funds.
Statewide Transportation Plan: Identifies regional transportation goals, issues, and needs and defines the direction for regional planning, programming, and project development over a 20-year period.
Glossary of Transportation Terms
Study Area: A geographic area selected and defined at the outset of engineering or environmental evaluations, which is sufficiently adequate in size to address all pertinent project matters occurring within it.
Study (or Project) Limits: The physical end points of a proposed project or study, usually designated at geographic or municipal boundaries, at interchanges, at roadway segments where cross sections change, or at the beginning or end of numbered state traffic routes.
Supplemental Agreement: An activity, study, survey, project, or other work related to transportation authorized in advance by the Federal Highway Administration, Federal Transit Administration, or other federal agency, and which is paid for either partially or fully by public funds.
Surface Transportation Program: A transportation funding program within TES-21. STP funds may be used for roadway construction and improvements, operational improvement, transportation systems, bicycle and pedestrian facilities, transit, ridesharing programs and facilities and transportation planning and studies.
Transportation Improvement Program (TIP): A three-year, prioritized program of transportation projects within a metropolitan or regional planning area proposed for federal funding. It includes all regionally significant projects, planning research activities and emergency relief projects.
Transportation Equity Act For The 21st Century (TEA-21): Signed by President Clinton in June 1998, this Federal transportation legislature retains and expands many of the programs created in 1991 under ISTEA. The legislation reauthorizes Federal surface transportation programs for six years (1998-2003), and significantly increases overall funding for transportation.
United States Department of Transportation (USDOT): The Federal Agency that establishes the nation’s overall transportation policy. Under its umbrella there are ten administrations whose jurisdictions include highway planning, development and construction; urban mass transit; railroads; aviation; and the safety of waterways, ports, highways, and oil and gas pipelines.
Wetlands: Those areas that are inundated or saturated by surface water or ground water at a frequency or duration sufficient to support, and under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions.