Metropolitan Planning Organization



Average Daily Traffic (or Average Daily Trips)
Clean Air Act
Federal Aviation Administration
Federal Highway Administration
Federal Transit Administration
Geographic Information Systems
High-Occupancy Vehicle
Interstate Highway System
Inspection and Maintenance
Major Investment Study
Management and Operations
Metropolitan Planning Organization
Metropolitan Statistical Area
Metropolitan Transportation Plan
Planning Funds
State Implementation Plan
State Planning and Research Funds
State Transportation Improvement Program
Transportation Equity Act for the 21st Century
Transportation Control Measure
Transportation Demand Management
Transportation Improvement Program
Transportation Management Area
Transportation System Management
Unified Planning Work Program


Capital Program
Funds Financial
Financial assistance from the Capital Program of 49 U.S.C. This program enables the Secretary of Transportation to make discretionary capital grants and loans to finance public transportation projects divided among fixed guideway (rail) modernization; construction of new fixed guideway systems and extensions to fixed guideway systems; and replacement, rehabilitation, and purchase of buses and rented equipment, and construction of bus-related facilities. 


Clean Air Act
Identifies actions to be taken by states and MPOs to reduce emissions from on-road mobile sources.


A transportation facility's ability to accommodate a moving stream of people or vehicles in a given time. 


The compliance of any transportation plan, program or project with air quality implementation plans. The CAA defines the conformity process.


Department of
When used alone, indicates U.S. Department of Transportation. In conjunction with a place name, indicates state, city or county transportation agency (Virginia DOT, etc.).


Emissions Budget
The part of the SIP that identifies the allowable emissions levels mandated by the NAAQS for certain pollutants emitted from mobile, stationary and area sources. The emissions budget is used for meeting emission reduction milestones, attainment or maintenance demonstrations.


Federal Highway
Administration          (FHWA)
A branch of the U.S. Department of Transportation that administers the Federal-Aid Highway Program, providing financial assistance to states to construct and improve highways, urban and rural roads, and bridges. The FHWA also administers the Federal Lands Highway Program, including survey, design and construction of forest highway system roads, parkways and park roads, Indian reservation roads, defense access roads and other federal lands roads.


Fiscal Constraint
Making sure that a given program or project can reasonably expect to receive funding within the time allotted for its implementation.


Federal Transit
Administration               (FTA)
A branch of the U.S. Department of Transportation that is the principal source of federal financial assistance to America's communities for planning, development and improvement of public or mass transportation systems. FTA provides leadership, technical assistance, and financial resources for safe, technologically advanced public transportation to enhance mobility and accessibility, to improve the nation's communities and natural environment, and to strengthen the national economy.


Geographic Information
System (GIS)
Computerized data management system designed to capture, store, retrieve, analyze and display geographically referenced information. 


Vehicle (HOV)
Vehicles carrying two or more people. The number that constitutes an HOV for HOV highway lanes may be designated differently by different transportation agencies.


Interstate Highway    System (HIS)
The system of highways that connects the principal metropolitan areas, cities and industrial centers of the United States. Also connects the United States to internationally significant routes in Canada and Mexico.


The ability to connect, and the connections between, modes of transportation. 


Land Use Refers to the manner in which portions of land or the structures on them are used; commercial, residential, retail, industrial, etc. 


Maintenance Area A probationary status for a region that is nonattainment for air quality but is taking the required steps to comply with the Clean Air Act. 


Transportation Plan    (MPO)
The official intermodal transportation plan that is developed and adopted through the metropolitan transportation planning process for the metropolitan planning area, in accordance with 23 U.S.C 134, 23 U.S.C. 135, and 49 U.S.C. 5303.


 Mobile Source Mobile sources are referred to as contributors to pollution. Some examples include motor vehicles, aircraft, seagoing vessels and other transportation modes. The mobile source-related pollutants are carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and small particulate matter (PM-10).


 Mode A specific form of transportation, such as automobile, subway, bus, rail or air.


 Nonattainment Any geographic area that has not met the requirements for clean air as set out in the Clean Air Act of 1990.


 Ozone (O3) Ozone is a colorless gas with a sweet odor. Ground-level ozone is not a direct emission from transportation sources. It is a secondary pollutant formed when volatile organic compounds, such as pesticides and solvents, and NOx combine in the presence of sunlight. Although the ozone in the upper atmosphere protects us from harmful ultraviolet rays, ground-level ozone is the main component of smog.


Indicators of how well the transportation system is performing with regard to such things as average speed, reliability of travel and accident rates. Used as feedback in the decision making process.


 Planning Funds (PL) Primary source of funding for metropolitan planning designated by the FHWA. 


The active and meaningful involvement of the public in the development of transportation plans and programs.


State Implementation    Plan (SIP) Produced by the state environmental agency, not the MPO. Contains specific strategies for controlling emissions and reducing ambient levels of pollutants, in order to satisfy the CAA requirements for demonstrations of reasonable further progress toward attainment. Must be taken into account in the transportation planning process. 


 Smart Growth A set of policies and programs design to protect, preserve, and economically develop established communities and valuable natural and cultural resources.


 Sources Refers to the origin of air contaminants. Can be point (coming from a defined site) or non-point (coming from many diffuse sources). Stationary sources include relatively large, fixed facilities such as power plants, chemical process industries and petroleum refineries. Area sources are small, stationary, non-transportation sources that collectively contribute to air pollution, and include such sources as dry cleaners and bakeries, surface coating operations, home furnaces and crop burning. Mobile sources include on-road vehicles such as cars, trucks, and buses; and off-road sources such as trains, ships, airplanes, boats, lawnmowers and construction equipment.


 Sprawl Urban form that connotatively depicts the movement of people from the central city to the suburbs. Concerns associated with sprawl include loss of farmland and open space due to low-density land development, increased public service costs, and environmental degradation as well as other concerns associated with transportation.


State Planning and Research Funds      (SP&R) Primary source of funding for statewide long-range planning.


Stakeholders Individuals and organizations involved in or affected by the transportation planning process. Includes federal/state/local officials, MPOs, transit operators, freight companies, shippers and the general public.


Statewide Transportation Plan The official statewide intermodal transportation plan developed through the statewide transportation planning process.


State Transportation
Improvement Program (STIP)
A staged, multi-year, statewide, intermodal program of transportation projects, consistent with the statewide transportation plan and planning processes as well as metropolitan plans, TIPs and processes. 


Surface Transportation Program (STP) Federal-aid highway funding program that funds a broad range of surface transportation capital needs, including many roads, transit, sea and airport access, vanpool, bike and pedestrian facilities.


Transportation Equity
Act for the 21st Century (TEA~21)
Authorized in 1998, TEA-21 authorized federal funding for transportation investments for fiscal years 1998-2003. Approximately $217 billion in funding was authorized, the largest amount is history, which is used for highway, transit and other surface transportation programs.


Control Measures    (TCM)
Specific measures that reduce emissions by reducing vehicle use or reducing traffic flow. Examples: improved public transit, high-occupancy vehicle lanes, shared-ride services, bicycle/pedestrian facilities, and flexible work schedules. 


Transportation Demand Management (TDM) Programs designed to reduce demand for transportation through various means such as the use of transit and alternative work hours. 


Telecommuting Communicating electronically (by telephone, computer, fax, etc.) with an office, either from home or from another site, instead of traveling to it physically.


 Title VI Title VI of the Civil Rights Act of 1964. Prohibits discrimination in any program receiving federal assistance. 


Improvement Program (TIP)
A document prepared by a metropolitan planning organization that lists projects to be funded with FHWA/FTA funds for the next one to three years. 


Management Area   (TMA)
All urbanized areas over 200,000 in population, and any other area that requests such designation.



 Trust Fund A fund credited with receipts that are held in trust by the government and earmarked by law for use in carrying out specific purposes and programs in accordance with an agreement or a statute.


Unified Planning  Work Program      (UPWP) The management plan for the (metropolitan) planning program. Its purpose is to coordinate the planning activities of all participants in the planning process.


 Urbanized Area Area that contains a city of 50,000 or more population plus incorporated surrounding areas meeting size or density criteria as defined by the U.S. Census.