I-95 Corridor Coalition

The I-95 Corridor Coalition is an alliance of transportation agencies, toll authorities, and related organizations, including public safety, from the State of Maine to the State of Florida, with affiliate members in Canada. The Coalition provides a forum for key decision and policy makers to address transportation management and operations issues of common interest. This volunteer, consensus-driven organization enables its myriad state, local and regional member agencies to work together to improve transportation system performance far more than they could working individually. The Coalition has successfully served as a model for multi-state/jurisdictional interagency cooperation and coordination for over a decade. Vermont is considered to be a part of the I-95 region.


A consequence of an effect generated by a Land Use. An impact is most often considered to be significant when it is experienced off of the Lot of the Land Use that generated the effect. See Adverse Impact and Impacts Analysis.

Impact Fee

A local government imposed fee upon developers, which in theory is used to finance infrastructure costs and improvements that handle increased service caused by new development.

Impacts Analysis (Impact Study)

The description and evaluation of the significance of one or more particular types of Impacts. Examples include environmental impact studies (EISs), fiscal impact analyses, and traffic impact studies. The term also refers to a formal method of assessing the impacts that flow from the effects caused by the activities associated with different types of Land Uses in order to determine the most appropriate strategies for balancing the costs and benefits of Land Development.

Impervious Surface

A man-made surface including paved and unpaved roads, parking areas, roofs, driveways, and walkways, from which precipitation runs off rather than infiltrates (10 VSA 1264 (6)).

Improved Land

A building site that already contains Improvements (such as streets, water supply systems, and sewage disposal systems), so that a developer of the site can focus development efforts on constructing Buildings.


The public Infrastructure and private utilities that are provided in a Land Development to make it an attractive site for a particular Land Use.

Improvements Agreement

A contract between a developer and a government that requires the developer to undertake certain actions (such as construct or install improvements) listed in the agreement according to certain specifications and conditions.

Incentive Zoning

An option provided to developers to be relieved of a specific Design Standard (typically within proscribed limits), in exchange for providing an amenity or development feature specified by the Bylaw.

Indirect Impacts

Impacts that are caused by an action (such as a transportation project) that occur later in time and farther removed in distance, but are still foreseeable. Also known as “Secondary Impacts.”

Induced Travel

Formally known as the “Traffic Inducement Effect”, it is a highly debated concept in transportation planning, which postulates that improvements intended to increase highway capacity are only a temporary solution. Simply stated, Induced Travel is any increase in daily travel (measured as Passenger Miles of Travel [PMT] or Vehicle Miles of Travel [VMT]) resulting from a change in the transportation system.

Infill Development

New development or redevelopment (often at greater intensity) on a site that is surrounded by pre-existing development.


Facilities (such as streets and utilities) that are necessary for the use and development of land. The term sometimes refers only to public facilities.


A way of entering or travelling to a location. Ingress generally describes vehicle or pedestrian movements from the perspective of driveways and walkways which provide “ingress to a property”, or more commonly “Ingress & Egress to a property” or “Access & Egress to a property”.

Innovative Finance

A broadly defined term that encompasses a combination of specially designed techniques to supplement traditional federal financing methods for transportation-related projects. Often in the form of “Public-Private Partnerships”, locally authorized “Tax-Increment Financing”, et al., Innovative Finance for transportation seeks to; 1. Maximize the ability of states and other project sponsors to leverage Federal capital for needed investment in the nation’s transportation system; 2. More effectively utilize existing funds; 3. Move projects into construction more quickly than under traditional financing mechanisms; and 4. Make possible major transportation investments that might not otherwise receive financing.

Inscribed Circle Diameter

Diameter of a Rotary, Roundabout, or Circulator intersection. Generally speaking, a smaller ICD of a modern roundabout keeps the traffic speed lower, and hence safer than the larger ICD’s commonly found with rotaries or traffic circles.

Institute of Transportation Engineers

Founded in 1930, the Institute of Transportation Engineers is an international educational and scientific association of transportation professionals who are responsible for meeting mobility and safety needs. ITE facilitates the application of technology and scientific principles to research, planning, functional design, implementation, operation, policy development and management for any mode of ground transportation. ITE further promotes professional development of its members, supports and encourages education, stimulates research, develops public awareness programs and serves as a conduit for the exchange of professional information.

Integrated Noise Model

A computer model that evaluates aircraft noise impacts in the vicinity of airports for environmental assessments and impact statements. The INM has many analytical uses, such as: 1. Assessing current aircraft noise impacts around a given airport or heliport, 2. Assessing changes in noise impact resulting from new or extended runways or runway configurations, 3. Assessing changes in noise impact resulting from new traffic demand and fleet mix, 4. Evaluating noise impacts from new operational procedures, 5. Evaluating noise impacts from aircraft operations in and around National Parks.

Intelligent Transportation Systems

Technology used to improve the efficiency of transportation systems.

Intercept Facility

Otherwise known as a “Satellite Facility”, an Intercept “Park & Ride” facility’s purpose is to provide a less expensive parking alternative to on-site locations within activity centers or the urban core area and reduce SOV use in activity centers. These facilities may capture outgoing as well as incoming activity center traffic and serve as a transfer point from car to shuttle or transit. Characteristics include an urban/activity area fringe location, high capacity, surface or structured parking, and high frequency shuttle/transit connections to activity centers. Implementation funding is likely to come from Congressional earmarks and/or public private ventures.

Interested Person (Party)

24 VSA 4465 (b) provides a lengthy detailed definition of this term for the purposes of Chapter 117. The term includes certain property owners, municipalities, groups of voters or real property owners, state agencies, and ACCD as being eligible to appeal municipal land development review decisions.

Interim Bylaws

A Bylaw adopted under 24 VSA 4415 that is in effect for a fixed time while the municipality is considering a new or amended Comprehensive Plan or Bylaw.


Planning that reflects a focus on connectivity between modes and emphasizes choices, coordination, and cooperation.

Intermodal Surface Transportation Efficiency Act of 1991

The purpose of this act was to develop a ‘National Intermodal Transportation System that is economically efficient, environmentally sound, provides the foundation for the Nation to compete in the global economy and will move people and goods in an energy efficient manner.’ This act established the provision that MPO’s undertake development of a Transportation Improvement Program (TIP), a long-range plan, and an annual work program. It also required for states; a statewide planning process, a statewide transportation plan, and a statewide transportation improvement program (STIP).

Intermodal Transfer Facility

Involves moving containers between rail and truck, or other modal combinations, and can increase efficient transportation services and energy efficiency because a train loaded with containers can carry the same load as dozens of trucks. Such service can contribute to reduced truck traffic on congested highways, reduced damage to highways from heavy trucks, and improved air quality.

International Organization for Standardization

Based in Geneva, Switzerland, ISO is a non-governmental organization (NGO) coordinating the publication and development of a host of International Standards for government, private-sectors. Such standards apply to equipment specifications, data transfer standards, monitoring standards, et al. The acronym “ISO” is derived from the Greek ‘isos’ (meaning “equal”). Hence “ISO” is applicable to any country or language as a mark of an international standard.

International Roughness Index

A pavement condition profiling indicator (used by HPMS, et al.) reflecting ride smoothness. IRI data is captured by a device mounted on a vehicle measuring suspension motion per distance travelled, and may be expressed in inches/mile (in/mi) or meters/kilometer (m/km). An IRI of 0m/km means that a roadway is perfectly smooth. And where there is no maximum for this indicator, it is generally accepted that an IRI of 8m/km is almost impassible unless vehicle speeds are greatly reduced.

Intersection Sight Distance

The AASHTO “Green Book” reference to the “Line of Sight” distance between a vehicle travelling on a roadway and a vehicle attempting to enter the roadway from an intersection or driveway.

Interstate Highway System

A subsystem of the NHS, the Interstate Highway System is also named the “Dwight D. Eisenhower National System of Interstate and Defense Highways”. The concept of the IHS was first formally studied under mandate by the Federal-Aid Highway Act of 1938, and was first authorized construction funds under the Federal-Aid Highway Act of 1952. It was not until the enactment of the Federal-Aid Highway Act of 1956, championed by President Eisenhower, that the Highway Trust Fund was established to finance construction of the entire network for the purpose of facilitating private and commercial transportation, and providing transportation routes for military supplies and troop deployments in case of an emergency or foreign invasion.

Interstate Maintenance Program

Federal program providing funding for resurfacing, restoring, rehabilitating and reconstructing (4R) most routes on the Interstate Highway System.