Glossary of Terms



Access, Accessibility
The opportunity to reach jobs, services, housing, recreation, shopping and entertainment within a reasonable time frame, and without being impeded by physical, social, or economic barriers. Enhancing mobility is one way of providing improved access.

The choice between mutually exclusive possibilities.

Alternatives to be Carried Forward
The second Concurrence Point in the NEPA/404 Process.  This is where the cooperating agencies agree on which alternatives merit detailed analysis.

A signalized street that primarily serves through-traffic and that secondarily provides access to abutting properties, with traffic signal spacing of 2.0 miles or less.

Average Daily Traffic (ADT)
The calculation of average traffic volumes in both directions of travel in a time period greater than one day and less than one year and divided by the number of days in that time period.

Area Business Task Force
A group of business leaders from the local community that provides input for study and advise on issues germane to the corridor business needs.



Base Year
The year chosen for the initial data to establish a point for future comparison.
Build/No Build
Conformity requirement that Metropolitan Planning Organizations must show that "building" or implementing a long-range plan or Transportation Improvement Program will provide more emissions reductions than "not building" or not implementing the same long-range plan and program.



The maximum sustainable flow rate at which vehicles or persons reasonably can be expected to traverse a point or uniform segment of a lane or roadway during a specified time period under given roadway, geometric, traffic, environmental and control conditions; usually expressed as vehicles per hour, passenger cars per hour or persona per hour.

Categorical Exclusion
A category of actions which do not individually or cumulatively have a significant effect on the human environment and for which, therefore, neither an environmental assessment nor an environmental impact statement is required. (40 CFR 15084)

Chicago Metropolitan Agency for Planning (CMAP)
Formed in 2005, CMAP integrates planning for land use and transportation in the seven counties of northeastern Illinois.  The legislation creating CMAP passed in August 2005.  The new organization combined the region's two previously separate transportation and land-use planning organizations -- Chicago Area Transportation Study (CATS) and the Northeastern Illinois Planning Commission (NIPC) -- into a single agency.

On August 8, 2005 the Chicago Area Transportation Study and the Northeastern Illinois Planning Commission were combined to form one agency, the Regional Planning Board.

Collector streets collect and distribute traffic between local streets and arterials by providing limited mobility in combination with land access.  Intersections on collector streets are spaced at 0.5 mile intervals or less.

Process to assess the compliance of any transportation plan, program or project with regional air quality control plans. The conformity process is defined by the Clean Air Act. Federal Highway funds are tied to the region's conformity determination.

Cooperating Agencies
Any Federal agency other than a lead agency which has jurisdiction by law or special expertise with respect to any environmental impact involved in a proposal (or a reasonable alternative) for legislation or other major Federal action significantly affecting the quality of the human environment.  A State or local agency of similar qualification may, by agreement with the lead agency, become a cooperating agency.  Following is a list of typical Cooperating Agencies:

  • U.S. Environmental Protection Agency (USEPA)
  • U.S. Fish and Wildlife Service (USF&W)
  • Federal Highway Administration (FHWA)
  • U.S. Army Corps of Engineers (USACE)
  • Illinois Department of Transportation (IDOT)
  • State Resource/Regulatory Agencies
  • Illinois Environmental Protection Agency
  • Illinois Natural History Survey
  • Illinois State Geological Survey
  • Illinois State Water Survey
  • Illinois Department of Natural Resources
  • Illinois Department of Agriculture
  • Illinois Historic Preservation Agency
  • Natural Resources Conservation Service
  • Illinois Nature Preserves Commission



The primary performance measure on interrupted flow facilities, especially at signalized intersections.  For this element, average stopped-time delay is measured, which is expressed in seconds per vehicle.

Design Hourly Volume (DHV)
The traffic volume for the design hour in the peak direction of flow.

Design Year
Roadway Improvement projects are typically designed for a 20 year planning horizon.  The proposed improvement needs to accommodate traffic projections 20 years into the future.

Design Concept



Environmental Impact Statement (EIS)
A detailed written statement, prepared for major Federal actions significantly affecting the quality of the human environment, which discusses the environmental impact of the proposed action; any adverse environmental effects which cannot be avoided should the proposal be implemented; alternatives to the proposed action; the relationship between local short-term uses of man's environment and the maintenance and enhancement of long-term productivity; and any irreversible and irretrievable commitments of resources which would be involved in the proposed action should it be implemented.
Note: Rollins Road will not require this level of detailed environmental report.

Environmental Studies
The investigation of potential environmental impact to determine the environmental process to be followed and to assist in the preparation of the environmental document.

Environmental Assessment (EA)
A concise public document that serves to briefly provide sufficient evidence and analysis for determining whether to prepare an environmental impact statement or a finding of no significant impact.

Environmental Protection Agency (EPA)
A US government agency that issues emissions standards and monitoring policies for environmental pollutants in air, water and soil.



Federally Funded/Regulated
Refers to the involvement of Federal funds and/or jurisdictional authority by any Federal agency for a proposed action.

Finding of No Significant Impact (FONSI)
A document by a Federal Agency briefly presenting the reasons why an action, not otherwise excluded, will not have a significant impact on the human environment and for which an environmental impact statement will not be prepared.

Functional Classification
The function of every street is to provide some combination of traffic movement and access to adjacent land. The conflicting goals between these mobility and land access functions inherently result in traffic flow and safety problems as well as livability impacts on adjacent land uses. General functional classifications are Expressway, Arterial, Collector, and Local Street.

Federal Highway Administration (FHWA)
A major agency of the US Department of Transportation (DOT), which is a cabinet level organization of the Executive Branch of the U.S. Government, led by the secretary of transportation.  FHWA is charged with the broad responsibility of ensuring that America's roads and highways continue to be the safest and technologically up to date. They monitor and approve projects under the federal funding process.

A multilane, divided highway with a minimum of two lanes for the exclusive use of traffic in each direction and full control of access without traffic interruption.

Functional Classification
A transportation facility defined by the traffic service it provides.



The Illinois Department of Transportation (IDOT) 
A state agency that is responsible for planning, construction and maintenance of Illinois' extensive transportation network which encompasses highways and bridges, airports, public transit, rail freight and rail passenger systems. The mission of IDOT is to provide safe, cost-effective transportation for Illinois in ways that enhance quality of life, promote economic prosperity and demonstrate respect for our environment. IDOT has jurisdiction over the IL 83 portion of the Rollins Road project.

An interchange is a system of interconnecting roadways in conjunction with one or more grade separations that provides for the movement of traffic between two or more roadways or highways on different levels.

An intersection is defined as the general area where two or more roadways join or cross, including the roadway and roadside facilities for traffic movements within the area.

Interstate System
The toll-free express highway network created as a result of the "Federal-Aid Highway Act of 1956." Currently per the FHWA website, the Interstate system is nearly 47,000 miles long.



Lead Agency
The agency or agencies preparing or having assumed primary responsibility for preparing the environmental document.  In the case of the Rollins Road project, this is Lake County Division of Transportation.

Level of Service (LOS)
A qualitative measure describing operational conditions within a traffic stream, based on service measures such as speed and travel time, freedom to maneuver, traffic interruptions, comfort and convenience.  Letter designations, A through F, have been correlated to quantitative measures based on the amount of delay experienced at an intersection. Level A represents the best conditions and level F the worst.

When designing new or rehabilitated highways in the Chicago region, the Illinois Department of Transportation estimates future traffic volumes (generally 20 years into the future) and strives to design intersections to operate at Level of Service "D" or better with Design Year traffic.

Local Streets
Local streets provide maximum land access and minimum mobility. Access to a local street is on an as needed basis to allow property owners access to a transportation facility.

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



A permissive condition allowing individual judgment and discretion in the evaluation and decision-making. If the term is used in specifying a procedure, that procedure is optional.

Metropolitan Planning Organization (MPO)
The Federal government and local officials designate local planning agencies to assure that projects undertaken with Federal funds are consistent with the regional transportation and land use planning in the area. For northeastern Illinois the MPO is the Chicago Area Transportation Study (CATS).

Mitigation includes the following items:

  • Avoiding the impact altogether by not taking a certain action or parts of an action.
  • Minimizing impacts by limiting the degree or magnitude of the action and its implementation.
  • Rectifying the impact of repairing, rehabilitating, or restoring the affected environment.
  • Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action.
  • Compensating for the impact by replacing or providing substitute resources or environments.

Mitigation Measures
Activities identified in the environmental process intended to lessen the severity of any unavoidable environmental impacts precipitated by the proposed action.

Major Investment
Major Investment Studies are initiated for significant highway and/or transit transportation investments.  During the MIS process, local governments, planners and project sponsors explore and analyze alternatives that can improve mobility and safety where the proposed improvement is located. Rollins Road is not a major investment study.

Metropolitan Planning Organization (MPO)
A transportation policy making organization made up of representatives from local government and transportation authorities.  In the early 1970's, congress passed legislation requiring formation of an MPO for any urbanized area with a population over 50,000.  MPO's are responsible for channeling federal funding through a consistent process.  As of 2005, there were 385 MPO's in the US.  The Chicago area MPO is CMAP.

A mathematical and geometric projection of activity and the interactions in the transportation system in an area. This projection must be able to be evaluated according to a given set of criteria which might include land use, economics, social values, and travel patterns.



National Environmental Policy Act of 1969 (NEPA)
Landmark environmental legislation which set forth a national policy and is the nation's legal basis for ensuring the protection and enhancement of the quality of the human environment. As such, it is the foundation of more specific environmental controls on the action of Federal agencies and other agencies who use Federal funds or engage in federally regulated activities. This Act and subsequent laws established the format and requirements for Environmental Impact Statements, Environmental Assessments, Categorical Exclusions, etc.

Transportation Network
 A series of roads or streets which permits vehicular movement.

National Ambient Air Quality Standards (NAAQS)
Federal standards that set allowable concentrations and exposure limits for various pollutants.



Ozone is a colorless gas with a sweet odor. Ozone is not a direct emission from transportation sources. It is a secondary pollutant formed when hydrocarbons (HC) and nitrogen oxides (NOx) combine in the presence of sunlight. Ozone is associated with smog or haze conditions.



Provides bus transportation primarily in the suburban areas outside of the City of Chicago.

Peak Hour
The single hour in the day during which the maximum traffic volume occurs on a particular roadway. Peak hours are further classified as an A.M. peak hour, a P.M. peak hour, or a weekend peak hour.

For purpose of the Federal flood plan regulations, means capable of being done within reasonable natural, social or economic constraints.

Purpose of and Need for Action
The Purpose and Need identifies and describes the proposed action and the transportation problem which it is intended to address.

Particulate Matter (PM), (PM 10)
Any material that exists as solid or liquid in the atmosphere. Particulate matter may be in the form of fly ash, soot, dust, fog, fumes, etc. Small particulate matter, or PM10, is less than 10 microns in size (about one-eighth the diameter of a human hair) and is too small to be filtered by the nose and lungs.

Public Participation (Public Involvement)
The movement of citizens in governmental decision-making processes.



Property owned by a government agency used for the construction of public facilities like a roadway or a bridge.



An early and open process for determining the scope of issues to be addressed in Environmental Impact Statements or Environmental Assessments and for identifying potentially significant issues related to the proposed action. Scoping is intended to focus the study effort on issues that are significant and avoid the collection of needless detailed information on insignificant issues.

Section 4(f) Land
Land protected under 49 USC 303 (Section 4(f) of the USDOT Act of
1966); i.e., any publicly owned park, recreational area, or wildlife and waterfowl refuge or a historic site (publicly or privately owned) of national, State, or local significance (as
determined by the Federal, State, or local officials having jurisdiction over the park,
recreational area, refuge or site). The term "historic site" includes both historic and
prehistoric archaeological sites determined important for preservation in place.

Section 404 Permit
Beginning in 1899 the U.S. Army Corps of Engineers was given regulatory function over public waterways. Public waterways at that time included rivers, harbors and other bodies of water which were navigable. In 1972 the Federal Water Pollution Control Act expanded the Corps regulatory function to include oversight of the "discharge of dredged material". Additionally, a definition of the "Waters of the United States" was also included in this law which expanded the Corps jurisdiction to include tributaries of navigable waters. In response to Section 404 of this 1972 law, a Federal permit process was established which requires that if a project will impact the Waters of the United States; all practical alternatives which avoid and minimize impacts must be evaluated.

Selected Alternative
The alternative chosen that best meets the goals for the project. This alternative is advanced forwarded through the Phase I environmental process.

Shall, Must
A mandatory condition. Users are obligated to adhere to the recommendations and applications presented in this context or to perform the evaluation indicated. If these terms are used in specifying a procedure, that procedure is mandatory.

An advisory condition. Users are strongly encouraged to follow the criteria and guidance presented in this context. If these terms are used in specifying procedures, that procedure is recommended. Deviations from the specified procedure should be justified.

Strategic Regional Arterial (SRA)
The Strategic Regional Arterial system is a network of approximately 1,500 miles of existing roads in northeastern Illinois. The system includes routes in Cook, DuPage, Kane, Lake, McHenry and Will Counties. Creation of the SRA system is a major component of Operation GreenLight, an eight-point plan to deal with urban congestion and improve regional mobility. The plan was developed by IDOT in cooperation with the Illinois State Toll Highway Authority (ISTHA), CATS, NIPC and the Regional Transportation Authority (RTA). The SRA system, which was first designated as part of the 2010 Transportation System Development Plan adopted by regional planning agencies and continues as a component of the 2020 Regional Transportation Plan, is intended to supplement the existing and proposed expressway facilities by accommodating a significant portion of long-distance, high volume automobile and commercial vehicle traffic in the region.



Transportation Improvement Program (TIP)
Document prepared by states and regional planning commissions (i.e., DRCOG) identifying projects to be funded under federal transportation programs for a full-year period. If it is not included in a conforming TIP, a project is ineligible for federal funding.

Travel Time
The average time spent by vehicles traversing a highway segment, including control delay, in seconds per vehicle or minutes per vehicle.



U.S. Department of Transportation (DOT)
A cabinet level organization of the U.S. Executive Branch of government, led by the secretary of transportation.  The U.S. DOT was established by an act of Congress on October 15, 1966.  The mission of the U.S. DOT is to serve the United States by ensuring a fast, safe, efficient, accessible and convenient transportation system that meets our vital national interests and enhances the quality of life of the American people, today and into the future.



Vehicle Miles of Travel (VMT)
A standard area wide measure of travel activity. Most conventional VMT calculation is to multiply the average length of trips by the total number of trips.



A geographical aggregation defined by land use, which generates trips within a corridor.