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6. Definitions of Terms Used

Transportation conformity: Process whereby a metropolitan planning organization or unit of government determines that a geographic area will adhere to the standards set out for any or all of six criteria pollutants listed in the Clean Air Act legislation, including any mitigating actions (control measures) required to meet the standards.

Boundary Effect: The influence that a major physical, or perceptual barrier may have on land use and travel behavior. Examples include freeways, rivers, changes in income of the population, and perceived crime rates.

Connectivity: The connectivity of a street or other transportation system refers to the number of alternative paths that can be traveled between two or more points within the system.

Cellular Automation, Cellular Automata: A modeling construct that uses a set of user-defined rules (called transition rules) to sequentially migrate the conditions of cells.

Density: Density refers to an increase in the number of units or number of square feet of development (e.g., houses, offices, hotels, shopping centers) in a given geographic area.

Design: Design describes the physical characteristics of a community, including building height, mass, setbacks, and architectural/structural features; and the transportation features like sidewalk widths, bicycle lanes, street widths, lighting, pedestrian furniture, street layouts, and cross-sections.

Diversity: Diversity is a measure of the number of different types of land uses contained within a given geographic area.

Edge Effect: Refers to the effect(s) that neighboring areas with different land uses may have on the area under consideration.

Elasticity: As referred to in economics, elasticity is the proportional change in one variable relative to the proportional change in another variable. See also Appendix D of this document for a complete definition.

End-User, End-User Community: End-User Communities are those agents or agencies that conduct or use the results from land use-emissions benefits studies, chiefly metropolitan planning organizations and state air agencies.

Gravity Model: The gravity model is a mathematical formula used to estimate the number of trips between any two points depending on the attraction and production potential of the two points and the distance between them.

Local Scale, Local Scale Research: A local scale refers to study areas that are community or neighborhood-based in physical scope, typically less than two square miles in total area.

Metropolitan Planning Organization (MPO): Agency charged with the process of carrying out a cooperative, continuous, and comprehensive framework for making transportation investment decisions in metropolitan areas. Program oversight is a joint FHWA/FTA responsibility. (source: AMPO)

Regional Scale, Regional Scale Research: This refers to a study area that is large in physical scope, typically encompassing a several-miles-long corridor, subarea greater than two square miles in size, or entire metropolitan planning and nonattainment/maintenance areas.

Smart Growth: Development policies that aim to prevent urban sprawl and pollution, and reduce the profligate use of non-renewable fuels, particularly an excessive dependency on private cars in industrialized countries. (source: Wikipedia, http://en.wikipedia.org/wiki/Smart_growth, August, 2004)

Spatial Autocorrelation: The relationship(s) (correlation) between variables associated with two or more physical locations separated in space.

State-of-the-Practice: Methods, techniques and procedures that define how the majority of agencies are successfully conducting land use-emissions benefits studies.

Sustainable Living, Sustainability, Sustainable Development: Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. (source: World Commission on Environment & Development. Our Common Future: The Bruntland Commission Report, 1987)

Updated: 07/06/2011
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