Glossary

Every trade has its acronyms, terms and buzzwords. The transportation industry is no different.
Below is a list of definitions of frequently used transportation jargon.

Affected Environment - The physical features, land, area, or areas to be influenced, or impacted, by an alternative alignment under consideration. This term also includes various social and environmental factors and conditions pertinent to an area.

Agency Coordination - A general term referring to the process whereby government agencies are afforded an opportunity to review and comment upon transportation proposals.

Alignment Studies - A general term describing engineering work involving the vertical and horizontal positioning, the adjusting and refining, and the comprehensive evaluation of a trial line or lines through a selected study corridor taking into account all relevant features, controls, travel desires, impacts, benefits and costs. Alignment studies are typically performed to assess the relative feasibility of a proposed transportation facility.

Alternative - One of a number of specific transportation improvement proposals, alignments, options, design choices, etc., in a defined study area. For a transportation project, alternatives to be studied normally include the no-action alternative, an upgrading of the existing roadway alternative, new transportation routes and locations, transportation systems management strategies, multi-modal alternatives, if warranted, and any combinations of the above.

Archaeologically Sensitive Shorelines – Shores of water bodies determined by the Maine Historic Preservation Commission (MHPC) to be likely to yield prehistoric artifacts, based on a predictive model using topography, hydrology, and surficial soil types to assess sensitivity.

Archaeologically Sensitive Surficial Deposits – Land forms that are likely locations of prehistoric settlements or gathering places, based on a MHPC predictive model that uses surficial geology (water bodies, alluvium, lake bottom deposits, glacial outwash, and eskers) to assess sensitivity.

Army Corps of Engineers (USACOE) – A federal agency that administers Section 404 of the Clean Water Act and Section 10 of the Rivers and Harbors Act; its regulatory programs address wetlands and waterways protection.

Arterials – Roads with high traffic volumes that provide linkage between major cities and towns and developed areas, capable of attracting travel over long distances. Basically, they provide service to interstate and intercounty travel demand. The arterial system typically provides for high travel speeds and the longest trip movements. The degree of access control on an arterial may range from full control (freeways) to entrance control on, for example, an urban arterial through a densely developed commercial area.

At-grade –The intersection of two roads, or a road and a railway, that cross at the same elevation.

At-Risk Watershed – Watersheds contributing to water bodies that are at risk of eutrophication due to new development and phosphorus-laden runoff. These water bodies include public drinking water supplies and waters that currently exhibit algal blooms or other signs of eutrophication. At-risk watersheds are defined according to criteria in Maine’s Stormwater Law (5 M.R.S.A. § 3331).

Attainment Area – A geographic area in which levels of a criteria air pollutant meet the health-based primary standard (National Ambient Air Quality Standard) for the pollutant. Attainment areas are defined using federal pollutant limits set by the U.S. Environmental Protection Agency (EPA).

Avoidance Alternative - A general term used to refer to any alignment proposal which has been developed, modified, shifted, or downsized to specifically avoid impacting one or more resources.

Best Management Practice (BMP) – A structural and/or management practice employed before, during and after construction to protect receiving water quality. These practices either provide techniques to reduce soil erosion or remove sediment and pollutants from surface runoff.

Biodiversity –The diversity of genes, species, and ecosystems. This term includes the entire hierarchy of ecological organization, and encompasses regional ecosystem diversity (landscape diversity), local ecosystem diversity (community diversity), species diversity, and genetic diversity within populations of a species.

Carbon Monoxide (CO) – A colorless, odorless, tasteless gas formed in large part by incomplete combustion of fuel. Full combustion activities (i.e. transportation, industrial processes, space heating, etc.) are the major sources of CO.

Categorical Exclusion - A classification given to federal aid projects or actions which do not individually or cumulatively have a significant impact on the environment. Categorical Exclusions do not require extensive levels of environmental documentation.

CEQ Regulations - Directives issued by the Federal Council on Environmental Quality, published in 40 CFR 1500-1508, which governs the implementation of the National Environmental Policy Act (NEPA) and the development and issuance of environmental policy and procedure for federal actions by public agencies. The regulations contain definitions, spell out applicability and responsibilities, and mandate certain processes and procedures for state agencies with programs which utilize federal aid funds.

Collector Roads – Roads characterized by a roughly even distribution of their access and mobility functions. These routes gather traffic from local roads and streets and deliver it to the arterial system. Traffic volumes and speeds will typically be lower than those of arterials.

Comment Period - The duration of time during which written comments or responses may be submitted to an agency which has distributed a document for review and comment. It can be applicable to all types of documents which are circulated, as well as to formal presentations such as those which may be given by transportation department officials at a public hearing.

Community Water Supply – A public water system that serves at least 25 residents throughout the year; comprised of one or multiple wells or reservoirs.

Conceptual Mitigation - The early, generalized identification of design, operational, or construction measures considered to avoid, minimize or compensate for anticipated environmental consequences. Typically, conceptual mitigation represents ideas talked about prior to the concluding stages of an environmental study.

Concurrence - Determination by the agency that information to date is adequate and the project can advance to the next stage of project development.

Construction Phase - The phase of the transportation project development process which involves in the physical act of building by a contractor the proposed project to all plans and specifications developed during final design.

Controlled-Access Highway – A highway that provides limited points of access and egress. Freeways, such as I-95, are controlled access highways in which access points occur only at interchanges. These highways serve mobility needs, and are designed to accommodate higher travel speeds.

Cooperating Agency - Any organization, other than the lead agency, which has jurisdiction by law or special expertise with respect to any environmental impact involved in a proposed action.

Cost Effectiveness – Cost effectiveness is an economic measure used to evaluate and compare the corridors of a study. Cost effectiveness is defined as the present value of a gross regional product (GRP) growth per dollar of construction cost. In this way, cost effectiveness compares the relative future economic benefits against the size of the investment required to generate those benefits.

Cumulative Impacts – The impacts on the environment that result from the incremental impact of a project when added to other past, present, and reasonable foreseeable future actions regardless of what agency or person undertakes such other actions.

Daily Traffic Volume – The number of vehicles that use a given roadway over a 24-hour period in both directions.

dB – Unit of measurement of sound level. A unit used to express relative difference in power or intensity, usually between two acoustic or electric signals, equal to ten times the common logarithm of the ratio of the two levels.

dBA –An abbreviation for A-weighted decibel. The decibel is a unit used to describe sound pressure levels on a logarithmic scale. For community noise impact assessment, an A-weighted frequency filter is used to approximate the way humans hear sound.

Deciduous – Refers to woody vegetation, such as oak or maple trees, that shed their leaves after the growing season.

Deer Wintering Yard – Areas of softwood-dominated forest that provide food resources and shelter for deer during severe winter conditions.

Demand – Vehicular traffic demand (volume) on a given highway segment, expressed in vehicles per day (vpd).

Demand Shift – The change in demand (volume) on a given highway segment, expressed in vehicles per day (vpd). Demand shifts can be caused by new corridors that provide a faster and/or shorter travel route.

Design Hour Volume (DHV) – The hour used for geometric design of highways, typically the 30th highest traffic volume of the year.

Direct Effects - Effects caused by a given action and occurring at the same time and place. Changes in noise levels, fill discharges in wetlands, and changes in visual conditions are some examples of direct effects.

Disadvantaged Population – A group of people, living in one area, who have a median income below the federal poverty level, or who exhibit other indicators of economic disadvantage.

Draft Environmental Impact Statement (DEIS) – The document prepared by the Federal Highway Administration (FHWA) in accordance with FHWA National Environmental Policy Act (NEPA) regulations (23 CFR Part 771). These regulations require that the EIS evaluate all reasonable alternatives considered, discuss the reasons that alternatives have been eliminated from detailed study, summarize the studies, reviews, consultations, and coordination required by environmental laws and Executive Orders.

Early Coordination - Communication undertaken near the beginning of the transportation study development process to exchange information and work cooperatively with agencies and the public in an effort to determine the type and scope of studies, the level of analysis, and related study requirements.

Edge Habitat – An area along a transitional zone between two or more vegetation cover types that provide feeding, breeding, nesting, or cover habitat for wildlife.

Endangered Species – Any species which is in danger of extinction throughout all or a significant portion of its range.

Engineering - A general term which refers to the systematic analysis and development of measurable physical data, using applied mathematical, scientific, and technical principles, to yield tangible end products which can be made, produced, and constructed.

Environment - The complex of social, natural, and cultural conditions which are present in the physical surroundings.

Environmental Assessment - A document prepared for federal actions which are not categorical exclusions and which do not clearly require an EIS. An environmental assessment provides the analysis and documentation to determine if an EIS or a Finding of No Significant Impact should be prepared.

Environmental Baseline - An inventory or summary assessment of environmental features present within a study area, usually performed during systems planning or early project development. This activity is used to provide environmental impact information as a basis for developing alternatives.

Environmental Feature - A general term to denote resources or objects, located in or adjacent to an existing or proposed transportation corridor. Features may include natural or physical resources, important structures, communities’ facilities, topographic features, and certain other land uses.

Environmental Justice – Executive Order 12898 requires each federal agency to “make achieving environmental justice part of its mission by identifying and addressing disproportionately high and adverse human health or environmental impacts on minority populations and low-income populations.”

Essential Fish Habitat (EFH) – Those waters and substrate necessary to fish for spawning, breeding, feeding, or growth to maturity, as defined by the regional Fishery Management Council.

Farmland Protection Policy Act (FPPA) – A statute enacted in 1981 by the United States Department of Agriculture (USDA) to ensure that significant agricultural lands be protected from conversion to non-agricultural uses. For highway projects receiving federal aid, the regulations promulgated under the FPPA (7 CFR Part 658, 1984) require a state highway authority (MaineDOT) to coordinate with the USDA Natural Resources Conservation Service. The FPPA regulates four types of farmland soils; prime farmland, unique farmland, farmland of state-wide importance, and farmland of local importance.

Farmland Soils – Soils suited to producing crops; those with soil quality, growing season and moisture supply needed to produce a sustainable yield when treated and managed using acceptable methods. Specifically, farmland soils are those soil types designated by the Natural Resources Conservation Service (NRCS) in accordance with the Farmland Protection Policy Act (FPPA) of 1981 by the United States Department of Agriculture (USDA).

Farmland Soils of Statewide Importance – Soils that are nearly Prime Farmland and that produce high yields of crops when treated and managed according to acceptable farming methods (see definition of “Prime Farmland Soil”).

Feasibility Study - A general term that refers to various types of systematic evaluations carried out to better assess the desirability or practicality of further developing a proposed action. Such studies are typically performed during the planning stages.

Federal Emergency Management Agency (FEMA) – A former independent agency that became part of the new Department of Homeland Security in March 2003 – is tasked with responding to, planning for, recovering from and mitigating against disasters.

Federal Highway Administration (FHWA) – The branch of the U.S. Department of Transportation responsible for administering the funding of federal-aid highway projects.

Federal-Aid System – The federal-aid system consists of those routes within Maine that are eligible for the categorical federal highway funds.

Federal Register - A daily publication of the U.S. Government Printing Office which contains notices, announcements, rulemaking and other official pronouncements of the administrative agencies of the U.S. Government. Various announcements and findings related to specific environmental matters and transportation projects and activities appear in this publication.

Final Design Phase - The phase of the transportation project development process which involves the preparation of detailed working drawings as well as specifications and estimates for approved transportation projects.

Final Environmental Impact Statement (FEIS) – The document prepared after circulation of a DEIS (or SDEIS) and consideration of comments received. FHWA NEPA regulations (23 CFR Part 771.125) require that the FEIS identify a preferred alternative, evaluate all reasonable alternatives considered, discuss and respond to substantive comments on the EIS, summarize public involvement, and describe the mitigation measures that will be incorporated into the proposed action.

Floodplain – The level area adjoining a river channel inundated during periods of high flow.

Floodway – The channel of a stream, plus any adjacent floodplain areas, that must be kept free of encroachment in order that the 100-year flood be carried without substantial increases in flood heights.

FONSI - A Finding of No Significant Impact is a document by a federal agency that briefly presents the reasons why an action, not otherwise excluded (§ 1508.4), will not have a significant effect on the human environment and for which an environmental impact statement therefore will not be prepared. It shall include the environmental assessment or a summary of it and shall note any other environmental documents related to it (§ 1501.7(a)(5)). If the assessment is included, the finding need not repeat any of the discussion in the assessment but may incorporate it by reference.

Forest Block – Units of forest uninterrupted by roadways or other disturbance.

Fragmentation – Subdivision of a forest or other habitat into isolated patches by roads, land clearing, or other human or natural alterations of the landscape, accompanied by the loss of a certain portion of the original habitat.

Functional Conflict – Highways provide a balance between providing access (with multiple access points) and mobility (with limited access points). Freeways are designed to maximize mobility and serve regional traffic demands as opposed to local roads (or collectors) that provide multiple access points to adjacent land uses (residences or businesses). Functional conflicts arise when regional traffic that would be better served on a freeway, uses local roads.

Geographic Information System (GIS) – A computer-based application used to perform spatial analysis.

Geometric Deficiency – A deficiency that occurs when a highway’s geometric characteristics (lane width, shoulder width, horizontal curvature, vertical grade, etc.) do not meet prevailing design standards.

Geometric Design - Those engineering activities involving standards and procedures for establishing the horizontal and vertical alignment and dimensions of a highway.

Glacial Outwash – Surficial sand and gravel sediments deposited ahead of a glacier by glacial meltwater.

Grade – The slope of a road along the direction of travel, normally characterized by the vertical rise per unit of longitudinal distance.

Grade separation – The intersection of two roads, or a road and a railway, that cross at different elevations. One roadway overpasses or underpasses the other roadway with a structure(s).

Gross Regional Product (GRP) – Gross Regional Product is one of the major economic indices of the socio-economic development of a region. GRP is equal to the total of added values in the regional economic industries, estimated as a difference between production and intermediate consumption.

Groundwater Recharge Protection Areas – Areas of land designated by water resource agencies through which rainwater or snowmelt percolate and replenish the underlying aquifer in the area of a public well. These areas require special protection because they directly affect the quality and safety of the public drinking water supply.

High Crash Location (HCL) – A High Crash Location is an intersection or highway segment that experiences an abnormally high number of crashes relative to the traffic demands that are served. For the State of Maine, the Maine Department of Transportation identifies HCLs.

Highway Reconstruction/Rehabilitation – Reconstruction of an existing highway is undertaken when the pavement structure or alignment of the existing facility is deficient. Reconstruction includes removal and replacement of the entire pavement structure, significant changes in the vertical or horizontal alignment, or addition of lanes. Rehabilitation includes resurfacing and other minor repairs intended to extend the service life of the existing facility and enhance highway safety.

Historic Resources – Properties, structures and districts that are listed in or have been determined to be eligible for listing in the National Register of Historic Places.

Hourly Traffic Volume – The number of vehicles that use a given road over a 1-hour period.

Hydric Soils – Soils that are saturated, flooded, or ponded long enough during the growing season to develop at least temporary conditions where there is no free oxygen in the soil around the roots. Hydric soils correspond to federally and state regulated wetlands in many circumstances.

Hydrologic Regime – The frequency and duration of inundation or soil saturation of a given area.

Impacts - A term to describe the positive or negative effects upon the natural or human environment as a result of a specific project or projects.

Impervious Surface – Relating to hydrology. A surface through which precipitation cannot penetrate, causing direct runoff or perching (examples include asphalt paving roofs, and densely compacted gravel).

Independent Utility - The ability of a transportation improvement to be usable and be a reasonable expenditure even if no additional transportation improvements in the area are made.

Indirect Effects - Effects caused by a given action, occurring later in time or farther removed in distance but which are reasonably foreseeable. Induced changes to land use patterns, population density or growth rate are examples.

Interagency Meeting - One of several scheduled gatherings held during the transportation project development process to present project studies and data to government agencies and to receive comments and responses to assist in further project development. Typically, these meetings are held to discuss such data as plans of study, project need analyses, alternatives analysis information, elimination of and selection of alternates, and environmental documents.

Interstate – A freeway-type highway that is part of the National Highway System.

Interstate Highway System – The network of Interstate Highways established by the Federal-Aid Highway Act of 1956. The statute established a 41,000-mile network of controlled-access highways (expanded to 42,000 miles by legislation in 1968) intended to connect all metropolitan areas with populations greater than 50,000 and all state capitals.

Integrated Transportation Decision-making (ITD) Process - The requirements of Maine's Sensible Transportation Policy Act (STPA) and the National Environmental Protection Act (NEPA) have been integrated within a single integrated transportation decision-making (ITD) process to guide the planning of new transportation construction projects in Maine.

Intelligent Transportation Systems (ITS) - The application of technology to goods and people movement in order to reduce delay and improve safety. The main applications of ITS in place today involve the monitoring of real time traffic flows and weather conditions and transmitting this information to the appropriate authorities and the motoring public. The authorities use this information to send the response teams to the scene of an accident, whether it be emergency medical teams or a hazardous material team. The motoring public is alerted to potential hazards or delays on roadways through the use of highway advisory radio (HAR), variable message signs (VMS), or broadcast radio traffic reports.

Labor Market Area (LMA) – Labor market areas are regional areas with a high concentration of employment opportunities. These are economically integrated units within which workers may readily change jobs without changing their place of residence.

Lacustrine – Of and related to lakes.

Land and Water Conservation Fund – A system for funding Federal, State and local parks and conservation areas, created by the Land and Water Conservation Fund Act of 1964.

Lead Agency - The federal project proponent taking primary responsibility for preparing an environmental document.

Legal Notice - A formal announcement or finding published in a periodical or newspaper to provide official public notice of an action or approval which is of public interest.

Level of Detail - A general term referring to the amount of data collected, and the scale, scope, extent, and degree to which item-by-item particulars and refinements of specific points are necessary or desirable in carrying out a study. Level of detail is an important factor in the quality of a study, the overall study costs, and the length of time needed to perform study work.

Limited-Access Facility – A highway where access to abutting properties is restricted or limited by control of the right-of-way.

Link – A new or existing highway segment between two defined end-points.

Local Roads and Streets – All public roads and streets not classified as arterials or collectors will have a local classification. Local roads and streets are characterized by many points of direct access to adjacent properties and have relatively minor role in accommodating mobility. Speeds and traffic volumes are usually low.

Logical Termini - Features such as cross route locations that are considered rational end points for a transportation improvement and which serve to make it useable.

Magnuson-Stevens Fishery Conservation and Management Act – Legislation (16 U.S.C. 1855(b)) governing all fisheries resources within 320 kilometers (200 miles) of the U.S. coast that established regional Fishery Management Councils and required the preparation of Fisheries Management Plans.

MaineDOT Highway Design Guide – A tool developed by the Maine Department of Transportation that provides guidance for the design of roads and highways in the State of Maine in addition to the Federal Highway Administration design criteria.

Maine’s Sensible Transportation Policy Act (STPA) – Maine’s Sensible Transportation Policy Act is a state law enacted in 1991 by the citizens of Maine that provides a decision making framework for examining a range of alternatives. The STPA is applicable to transportation planning decisions, capital investment decisions, and project selection decisions made by the Maine Department of Transportation.

Major Collector Road – Collector Roads that tend to serve higher traffic volumes than other Collector Roads. Major collector roads typically link arterials. Traffic volumes and speeds will typically be lower than those of Principal Arterials.

Mesoscale Air Quality Analysis – A regional-level analysis of air for chemical constituents

Microscale Air Quality Analysis – An analysis of air for chemical constituents, typically conducted for a small study area such as an intersection.

Minor Arterial – Minor arterials are highways that tend to link Collector Roads to Principal Arterials and serve lower traffic volumes than typical arterials. Minor Arterials are also typically designed at lower travel speeds than Principal Arterials.

Mitigation – Actions that avoid, minimize, or compensate for potential adverse impacts.

Mitigation Measures - Specific design commitments made during the environmental evaluation and study process which serve to moderate or lessen impacts deriving from the proposed action. In accordance with CEQ, mitigation includes avoidance, minimization, rectification, reduction and compensation.

National Ambient Air Quality Standards (NAAQS) – The prescribed level of pollutants in the outside air that cannot be exceeded during a specified time in a specified geographic area.

National Environmental Policy Act of 1969, as amended (NEPA) – The federal legislation that requires an interdisciplinary approach in planning and decision-making for federal-aid actions. The Act includes requirements for the contents of environmental impact statements that are to accompany every recommendation for major federal actions significantly affecting the quality of the human environment. The interdisciplinary study approach includes the analysis of potential impacts to the natural, social and economic environment.

National Highway System (NHS) – The National Highway System is a system of those highways determined to have the greatest national importance to transportation, commerce and defense in the United States. It consists of the Interstate highway system, logical additions to the Interstate system, selected other principal arterials, and other facilities that meet the requirements of one of the subsystems within the NHS.

National Historic District – An area, comprising numerous buildings and their setting, identified as historic in the National Register of Historic Places.

National Priority List (NPL) – The “Superfund” statute (42 U.S.C. Sect. 9601) requires the EPA to establish a National Priorities List of sites which are to be given top priority consideration for removal of hazardous substances and remedial action.

National Register of Historic Places (National Register) – A list of structures, sites and districts of national historical significance as determined by the Advisory Council on Historic Preservation under the National Historic Preservation Act of 1966, as amended.

National Wetlands Inventory (NWI) – A program administered by the U.S. Fish and Wildlife Service for mapping and classifying wetland resources in the United States.

Natural Resources Conservation Service (NRCS) – Formerly the Soil Conservation Service, NRCS is a department within the United State Department of Agriculture that is responsible for administering the Farmland Protection Policy Act.

Needs Analysis - Data collection and analysis to document the purpose and need for the project. This document may draw on any number of transportation, master planning, socioeconomic, traffic, safety, system linkage, growth management or other community or regional issues of importance.

New Location Highway – A highway proposed to be constructed on land not currently used for transportation facilities.

Nitrogen Oxides (NOx) – Nitric oxide (NO) and Nitrogen dioxide (NO2) are collectively referred to as oxides of nitrogen (NOx). NO forms during high temperature combustion process. NO2 forms when NO further reacts in the atmosphere. NOx reacts with the sunlight to form ozone, a colorless gas associated with smog or haze conditions. Ozone is a pollutant regulated by the Clean Air Act Amendments of 1990.

No-Build Alternative - Normally includes short-term, minor restoration types of activities (e.g. safety and maintenance improvements) that maintain continuing operation of an existing facility. The no-build alternative serves as a baseline for the comparison of other alternatives.

Noise Abatement Criteria (NAC) – Noise levels measured in decibels that are used as a basis of comparison for evaluating the impact from predicted design year noise and for determining whether noise abatement measures should be considered.

Noise Abatement Measures – Actions that reduce traffic noise impacts. Noise abatement measures can be traffic management measures, alteration of horizontal and vertical alignments, acquisition of property rights for construction of noise barriers, construction of noise barriers, acquisition of real property or interest for buffer zones, or noise insulation of public use or nonprofit institutional structures.

Noise Receptor – Locations that may be affected by noise: Sensitive receptors include residences, parks, schools, churches, libraries, hotels, and other public buildings.

Non-Community Drinking Water System – A public water system that serves at least 25 persons at least 60 days out of the year and is not a community or a seasonal water system.

Non-Point Source Pollution (NPS) – Pollution of water bodies that does not originate at a single specific source such as an industrial discharge or discharge from a wastewater treatment plant. Sources of non-point pollution include runoff from highways, agricultural fields, golf courses, and lawns.

Other Principal Arterial – Highways that provide access between arterials and a major port, airport, public transportation facility or other intermodal transportation facility. Other Principal Arterials tend to serve lower traffic demands than Principal Arterials.

Outstanding River Segment (ORS) – A section of a river or stream designated by the Maine Natural Resources Protection Act (12 M.R.S.A. § 403) for protection because of the special resource values of its flowing waters and shorelines.

Ozone – A gas which is a variety of oxygen. Ozone is a pollutant regulated by the Clean Air Act Amendments of 1990. Ground-level ozone is the main component of smog. Ozone is not directly emitted by motor vehicles, but is formed when oxides of nitrogen react with sunlight.

Palustrine – The group of vegetated wetlands traditionally called by such names as marsh, swamp, bog, fen, and prairie. Palustrine wetlands may be situated shoreward of lakes, river channels, or estuaries; on river floodplains; in isolated catchments; or on slopes.

Palustrine Forested Wetland (PFO) – A palustrine wetland dominated by trees, commonly referred to as a swamp.

Palustrine Emergent Wetland (PEM) – A palustrine wetland dominated by herbaceous species, typically cattails, sedges and grasses, commonly referred to as a marsh.

Palustrine Scrub-Shrub Wetland (PSS) – A palustrine wetland dominated by shrubs.

Peak Hour – The hour of the day when traffic volume on a given roadway is highest. A separate peak hour can be defined for morning and evening periods.

Peak Hour Volume – The traffic volume that occurs during the peak hour, expressed in vehicles per hour (vph). Peak hour volumes are typically 10 to 15 percent of daily volumes.

Peak Hour Leq – Represents the noisiest hour of the day/night and usually occurs during peak periods of motor vehicle traffic. The Leq is the equivalent sound level measurement, which means it averages background sound levels with short-term transient sound levels and provides a uniform method for comparing sound levels that vary over time.

Permit - Written permission given by a governmental agency to take certain action during specific steps of the transportation project development process. Permits may include permission for any construction, excavation, depositing of material, or other work in navigable waters (Corps of Engineers), permission required for the discharge of dredged or fill material into waters of the United States (Corps of Engineers), and permission to construct bridges, causeways, and drawbridges in navigable waters (U.S. Coast Guard). A permit may also refer certain other clearances or certifications such as a clearance from the Federal Aviation Administration for proposed highway construction in the vicinity of public use and military airports, and water quality certifications for the licensing of an action that would result in a discharge into regulated waters. These approvals, plus certain others relating to solid waste management, underground storage tanks, coastal zone areas, etc., involve approvals and documentation commonly referred to as permits.

Plan of Study - A detailed, item-by-item outline of the objectives, scope, methodology and schedules for the analysis and development of a particular transportation project.

Posted Speed Limit – The speed posted for a facility based on engineering and traffic investigation.

Preliminary Engineering - A general term to describe 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.

Primary/Direct Impacts – The immediate effects on the social, economic, and physical environment caused by the construction and operation of a highway; these impacts are usually experienced within the right-of-way or in the immediate vicinity of the highway or other element of the proposed action.

Prime Farmland Soil – Soil map units that are designated by the Natural Resources Conservation Service as having the properties needed to produce sustained high yield crops when managed with modern farming techniques.

Principal Arterials – Highways in rural and urban areas that connect urban areas, international border crossings, major ports, airports, public transportation facilities or other intermodal transportation facilities.

Project Development - The overall process of advancing a transportation project from concept to implementation. Project development typically encompasses environmental and engineering tasks including planning, location, preliminary design, final design, and construction.

Public Hearing - A meeting designed to afford the public the fullest opportunity to express opinions on a transportation project. A verbatim record (transcript) of the proceedings is made part of the project record.
Public Involvement - These activities which present information to the public, seek public comments, and which serve to ensure consideration of public opinion.

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.

Rare and Exemplary Natural Community – An assemblage of interacting plants and animals and their common environment, recurring across the landscape, in which the effects of recent human interference are minimal. Rare natural communities are those which occur infrequently. Exemplary natural communities are exceptional representatives of more common natural communities.

RCRA Generator – An entity that produces hazardous waste regulated under the Resource Conservation and Recovery Act (RCRA) (42 U.S.C. sect. 6901), which mandates the appropriate identification, tracking, and disposal of hazardous waste.

Record of Decision (ROD) – The document, prepared by the Federal Highway Administration, that presents the basis for the Federal agency action, summarizes any mitigation measures to be incorporated, and documents any required Section 4(f) approvals. No Federal agency action may be undertaken until a Record of Decision has been signed. A Record of Decision is prepared no sooner than 30 days after the public release of the FEIS.

Relocations – The displacement of a residence, business or other structure from a property owner, for public use, that requires the residents or business to be moved to an alternate location.

REMI Model – The REMI Model (Regional Economic Models Inc.) is a widely used and accepted econometric model maintained and updated by the Center for Business and Economic Research at the University of Southern Maine.

Riparian – An area of land that encompasses and is contiguous to a stream or other water body.

Riverine – Of and relating to rivers.

Rural – A rural community is defined as an area with: a population less than 2,500 persons or; a population between 2,500 and 6,000 persons and a worker-to resident worker ratio less than 1.0.

Safety Deficiency – In the context of this study, a safety deficiency is a highway segment or intersection that contains a high crash location (HCL).

Secondary Impacts – Impacts that are caused by the proposed action and are later in time or farther removed in distance, but are still reasonably foreseeable; secondary impacts may include induced changes to land use patterns, population density or growth rate, and related effects on natural systems, including ecosystems.

Section 10 of the Rivers and Harbors Act of 1899 (Section 10) – Legislation (33 U.S.C. Section 403) that resulted in a permit being required from the Army Corps of Engineers for projects requiring construction in or over navigable waters, the excavation from or dredging or disposal of materials in such waters, or any obstruction or alteration in a navigable water (e.g. stream channelization).

Section 106 of the National Historic Preservation Act (Section 106) – The National Historic Preservation Act of 1966 (16 U.S.C. 470f), Section 106, requires Federal agencies to take into account the effect of their undertakings on properties included in or eligible for inclusion in the National Register of Historic Places and to afford the Advisory Council on Historic Preservation the opportunity to comment on such undertakings.

Section 4(f) of the Department of Transportation Act of 1966 (49 U.S.C., Section 303) (Section 4(f)) – Legislation protecting publicly owned parks, public recreation areas, historic properties or wildlife and waterfowl refuges. The statute states that no Department of Transportation project may use land from these areas unless there is demonstrated to be no prudent and feasible alternative to using the land, and the project includes all possible planning to minimize harm resulting from the use.

Section 404 of the Clean Water Act (Section 404) – The Federal Water Pollution Control Act Amendments of 1972 (33 U.S.C. 401 et seq.) is the enabling legislation for protection of waters of the United States by the Army Corps of Engineers and the U.S. Environmental Protection Agency.

Section 6(f) of the Land and Water Conservation Funds Act of 1963 (Section 6(f)) – Legislation that provides for the public purchase and preservation of tracts of land.

Sight Distance – The distance that a driver can see along the roadway before curvature or obstructions block the view.

Significant Impacts - Any number of social, environmental, or economic effects or influences which may be brought about as a result of the implementation of a transportation improvement. "Significant impacts" may include effects which are direct, secondary, or cumulative. The term "significant" is used and interpreted by the FHWA in determining which type of NEPA document is appropriate. Categorical exclusions are those actions which do not involve significant effects. Environmental Impact Statement projects in most cases can and do involve significant impacts.

Significant Wildlife Habitat – Wildlife habitats, including deer wintering yards, waterfowl and wading bird habitat, seabird nesting habitat, and significant vernal pools, that are protected under 38 M.R.S.A. § 480-B.

State Implementation Plan (SIP) – A plan created under The 1990 Clean Air Act Amendments (CAAA) that establishes emission reduction requirements for ozone and carbon monoxide non-attainment areas. Proposed projects must demonstrate that the impacts of their emissions are consistent with the appropriate SIP.

Stormwater Pollution Prevention Plan (SWPPP) – A plan required for major construction projects under the EPA’s National Pollutant Discharge and Elimination System (NPDES) general permit for construction activities. The SWPPP is required to address measures to prevent erosion, sedimentation, and other potential discharges of pollutants to water bodies and wetlands.

Stormwater Runoff – The portion of precipitation that flows toward stream channels, lakes, or other water bodies as surface flow.

Study Area - An identified amount of land or topography selected and defined at the outset of engineering or environmental evaluations, which are sufficiently adequate in size to fully identify, analyze and document impacts and effects for proposed projects within its boundaries.

Study Need - A detailed explanation of the specific transportation problems or deficiencies which have generated the search for improvements. It should refer to technical information, as necessary, such as measures of traffic efficiency or demand (origin-destination patterns, modal links, queue lengths, motorist delays, level of service, etc.) and other goals (economic development, safety improvement, legislative directives, etc.). Much of this information should be generated by the transportation planning process at a very early stage. The explanation of need should be a problem statement discussion, not a solution oriented discussion.

Study Purpose - A broad statement of the overall intended objective to be achieved by a proposed transportation facility. Normally, the purpose can be defined in just a few sentences. For instance, it may address expanded capacity in a given transportation corridor to facilitate the safe and efficient movement of people and goods, or improved access to a given area or community.

Supplemental Draft Environmental Impact Statement (SDEIS) – The document prepared by the Federal Highway Administration (FHWA) in accordance with FHWA National Environmental Policy Act (NEPA) regulations (23 CFR Part 771.130). An EIS shall be supplemented when the Administration (FHWA) determines that: 1) Changes to the proposed action would result in significant impacts not evaluated in the DEIS; or 2) New information or circumstances relevant to environmental concerns and bearings on the proposed action or its impacts would result in significant environmental impacts not evaluated in the DEIS. An SDEIS document generally presents new and updated information with regard to changes in the study and environment that have occurred since the publication of a DEIS.

Surface Water Supply Watershed – The watershed that contributes to a public drinking water supply.

System Compatibility – System compatibility describes how well alternatives, either new highways or upgrades, fit into the existing highway network and the planned transportation improvement plan.

System Continuity – System continuity is defined by how often highways transition between wide, higher speed segments to narrow, low speed segments.

System Linkage - A planning concept referring to the interconnecting of roadways which comprise an overall transportation network. A discussion as to how a proposed project fits into the existing and future transportation system (network), and how it contributes to developing a sound transportation network in an area or region is termed "system linkage". In describing the above concept, the terms connector road, missing link, gap completion, circumferential link, etc., are sometimes used.

System Planning - A methodical approach to the formulation of plans and programs for safe, efficient, and balanced transportation networks. The process involved with system planning includes the setting of goals and objectives, the collection of data of existing conditions, the simulation of future activities, the formulation of alternative planned changes, the evaluation of the changes against the desired goals and objectives, and decisions as to recommendations that are feasible, desirable, and appropriate.

Threatened Species – Any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.

Traditional Cultural Property (TCP) – A property or site that is eligible for inclusion in the National Register of Historic Places because of its association with cultural practices or beliefs of a living community that are rooted in that community’s history and are important to maintaining the continuing cultural identity of the community.

Transportation Deficiencies – A highway related facility that is unable to safely and efficiently satisfy travel demands because of the intensity of traffic volumes, capacity, and/or safety.

Transportation Demand Management (TDM) – A system of actions whose purpose is to alleviate traffic problems through improved management of vehicle trip demand as opposed to adding new highway segments.

Transportation Project Development Process - An interactive, multi-phase series of activities typically spanning a period of years which involve comprehensive planning, prioritization, detailed engineering and environmental studies, and agency and public involvement which lead to the selection, design, and construction of identified transportation improvements.

Transportation Systems Management (TSM) – Relatively low cost measures to increase capacity and/or provide safety improvements on the existing transportation system. These measures typically include traffic signal timing or phasing adjustments, designation of turning lanes at specific intersection or driveways, access management improvements, and enhanced signage or markings.

Unfragmented Habitat Block – An undeveloped area that is not impacted by roads or development.

U.S. Department of Agriculture (USDA) – A federal agency responsible for administering programs that address farming issues.

U.S. Environmental Protection Agency (EPA) – A federal agency responsible for administering programs that address environmental issues.

U.S. Fish and Wildlife Service (USFWS) – A federal agency responsible for addressing the protection of fish and wildlife including rare, threatened, or endangered species. The USFWS plays an advisory role in the Section 404 regulatory program administered by the U.S. Army Corps of Engineers.

Upgrade – A geometric improvement to an existing highway segment.

Urban – An urban community is defined as an area with: a population greater than 7,500 persons or; a population between 2,500 and 7,500 persons and a worker-to resident worker ratio greater than 1.0.

Vegetation Cover Type – A biological community characterized by certain vegetation characteristics, such as hardwood forest, mixed forest, shrub, herbaceous, and urban or residential managed vegetation.

Vehicle-Hours Traveled (VHT) – VHT is a measure of automobile use and trip time. One vehicle traveling one hour constitutes one vehicle-hour.

Vehicle-Miles Traveled (VMT) – VMT is a measure of automobile use and trip length. One vehicle traveling one mile constitutes one vehicle-mile.

Vernal pool – A temporary pool of surface water that provides breeding habitat for certain amphibian and invertebrate species.

Volatile Organic Compounds (VOCs) – Colorless gaseous compounds originating, in part, from the evaporation and incomplete combustion of fuels. In the presence of sunlight VOCs react to form ozone, a pollutant regulated by the Clean Air Act amendments.

Waterfowl and Wading Bird Habitat (WWH) – Wetlands that provide habitat for waterfowl (geese, brant, ducks) and wading birds (heron, egrets, bittern, rails), and that meet certain criteria for size, quality, and percent open water as established by Department of Inland Fish and Wildlife regulations.

Watershed – A region or area that contains all land ultimately draining to a water course, body of water, or aquifer.

Wellhead Protection Area (WPA) – Areas of land where human activities are regulated to protect the quality of ground water that supplies public drinking water wells.

Wetland – Areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions.

Wild and Scenic River – A river or river segment, designated by the National Park Service, because of the outstandingly remarkable scenic, recreational, geologic, fish and wildlife, historic, cultural or other similar values (16 U.S.C. 1271-1287).