Glossary & Acronyms


The following presents definitions for a number of terms frequently used during the development of environmental and design studies associated with the implementation of a transportation improvement.

Accessible Pedestrian Signal (APS)
A traffic signal that provides auditory and/or vibrotactile information to pedestrians who are blind or have low vision.

Adaptive Signal Control (ASC)
To ease traffic congestion, adaptive signal control (ASC) technology adjusts the traffic signal timings of a network in reaction to changing traffic patterns.

Arterial streets provide high mobility with limited land access allowed. Intersections are spaced in 0.5 to 2 mile intervals in an attempt to increase mobility.

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.

Bicycle Facilities
A general term denoting improvements and provisions made by public agencies to accommodate or encourage bicycling, including parking and storage facilities, and shared roadways not specifically designated for bicycle use.

A generic term for any road, street, path that is specifically designated for bicycle travel, regardless of whether such facilities are designated for the exclusive use of bicycles or are to be shared with other transportation modes.

Bike Lane
An undivided, paved, signed and marked portion of a roadway, sharing the same right-of-way with motorized vehicles, but designated for the preferential or exclusive use of bicyclists.

Bus-Rapid Transit (BRT)
Bus-rapid transit (BRT) systems provide more effective and efficient bus service by dedicated bus lanes, transit signal priority, and/or fewer stops on the route.

Capacity Analysis
A study done to determine the quality of operation of a given intersection or roadway segment. The quality of operation is expressed in terms of a Level of Service (LOS).

Categorical Exclusion (CE)
A category of actions which do not individually or cumulatively have any significant environmental impacts. They are actions that:

  • do not induce significant impacts to planned growth or land use for the area;
  • do not require the relocation of significant numbers of people;
  • do not have a significant impact on any natural, cultural, recreational, historic, or other resource;
  • do not involve significant air, noise, or water quality impacts; and
  • do not have significant impacts on travel patterns;

Chicago Metropolitan Agency for Planning (CMAP)
The Chicago Metropolitan Agency for Planning (CMAP) is the comprehensive regional planning organization for the northeastern Illinois counties of Cook, DuPage, Kane, Kendall, Lake, McHenry, and Will. By state and federal law, CMAP is responsible for producing the region's official, integrated plan for land use and transportation. The agency's innovative GO TO 2040 planning campaign will develop and implement strategies to shape the region's transportation system and development patterns, while also addressing the natural environment, economic development, housing, education, human services, and other factors shaping quality of life.

Chicago Transit Authority (CTA)
Providing public transportation service to the City of Chicago and 40 surrounding suburban communities, the CTA manages the second-largest transit system in the United States, providing more than 521 million unlinked passenger trips in 2009. The CTA operates seven rapid transit rail lines covering 144 rail stations and more than 140 bus routes serving more than 12,000 posted bus stops. While rail services provide more than 750,000 trips, buses provide more than 1 million trips daily.

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.

Complete Streets
Complete Streets are designed, operated and maintained so they are safe, comfortable and convenient for all users – pedestrians, bicyclists, transit users, freight, and motorists of all ages and abilities.

Context Sensitive Solutions (CSS)
Context sensitive solutions (CSS) is a collaborative, interdisciplinary approach that involves all stakeholders to develop a transportation facility that fits its physical setting and preserves scenic, aesthetic, historic, and environmental resources, while maintaining safety and mobility.

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 qualifications may, by agreement with the lead agency, become a cooperating agency.

Corridor Planning Committee (CPC)
A working group consisting of community leaders and other interests. The Corridor Planning Committee (CPC) helps the Project Study Group (PSG) identify community issues and helps determine community characteristics which should be taken into consideration in the planning process.

Design Hourly Volume (DHV)
The two-way traffic volume for the design hour. In urban areas, the Peak Hour is used as the Design Hour.

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.

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

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

Functional Classification
The assignment of roads into categories according to the character of service they provide in relation to the total road network to assist in determining appropriate regulatory controls and roadway design criteria.

Geographic Information System (GIS)
Geographic information system (GIS) combines hardware, software, and data. GIS organizes the data in many ways that can display patterns and trends.

Intelligent Transportation Systems (ITS)
Encompass a broad range of communications based information, control and electronics technologies. When integrated into the transportation system infrastructure, and in vehicles themselves, these technologies help monitor and manage traffic flow, reduce congestion, provide alternate routes to travelers, enhance productivity, respond to incidents, adverse weather or other road capacity constricting events.

Denotes the seamless movement of people or cargo between transport modes (e.g., rail to heavy truck).

Intermodal Facilities
Transportation facilities that provide for linkages between travel modes, transferring freight from ship to truck, for example, or ship to rail, or rail to truck.

The general area where two or more roadways join or cross, including the roadway and roadside facilities for traffic movements within the area.

Lead Agency
The agency assumed to have primary responsibility for overseeing the implementation of a transportation improvement or planning/environmental study.

Level of Service (LOS)
A qualitative concept which has been developed to characterize degrees of congestion as perceived by motorists. 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.

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.

Long Range Transportation Plan (LRTP)
A long-range (20 to 25-year) strategy and capital improvement program developed to guide the effective investment of public funds in transportation facilities that takes into account all modes of transportation including automobile, bicycle, rail, surface freight, and pedestrian travel.

The Northeast Illinois Regional Commuter Railroad, also known as Metra, operates a vast system of commuter passenger rail services spanning 11 rail lines which serve a combined total of 241 stations . Metra provides more than 81.3 million passenger trips annually , many of which originate in neighboring counties, including those of DuPage, Kane, Lake, McHenry, and Will.

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 Metropolitan Agency for Planning (CMAP).

Metropolitan Transportation Plan (MTP)
Metropolitan transportation planning is the process of examining travel and transportation issues and needs in metropolitan areas. It includes a demographic analysis of the community in question, as well as an examination of travel patterns and trends. The planning process includes an analysis of alternatives to meet projected future demands, and for providing a safe and efficient transportation system that meets mobility while not creating adverse impacts to the environment. In metropolitan areas over 50,000 populations, the responsibility for transportation planning lies with designated Metropolitan Planning Organizations (MPO). MTP has taken over what the federal government had previously termed Long-Range Transportation Plans (LRTP) as such relates to the responsibilities of MPOs.

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.

Moving Ahead for Progress in the 21st Century (MAP-21)
MAP-21 is a milestone for the U.S. economy and the Nation’s surface transportation program. By transforming the policy and programmatic framework for investments to guide the system’s growth and development, MAP-21 creates a streamlined and performance-based surface transportation program and builds on many of the highway, transit, bike, and pedestrian programs and policies established in 1991.

Any planning process, capital improvement, or transportation system which takes into account all available modes of travel including vehicle, transit - bus, transit - rail, freight –rail, freight –truck, bicycle, and pedestrian activity.

National Environmental Policy Act of 1969 (NEPA)
Landmark environmental legislation which set forth a national policy for 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 that 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.

Pace Suburban Bus
As one of the largest public bus service providers in the US, Pace operates 209 fully-accessible bus routes within the six county area of Cook, DuPage, Kane, Lake, McHenry, and Will, which includes 284 municipalities. Besides traditional fixed-route bus service, Pace provides paratransit service via 454 vehicles as well as vanpool service via 694 vehicles. Ridership stood at nearly 40 million in 2012, with vanpool ridership at 2.2 million that same year.

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.

Pedestrian Hybrid Beacon (PHB)
A pedestrian hybrid beacon is a device that stops traffic to allow pedestrians to cross. The beacon flashes yellow, then is steady yellow, then a steady red, then flashes red to make drivers aware to stop.

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.

Queue Jump
Queue jumps are sections of roadway lane space that are typically dedicated for buses to use to “jump” in front of traffic that is stopped at an intersection. The lanes are usually located on the far side of an intersection at a bus stop or boarding location, and are equipped with electronic sensors that detect when a bus is present. The system can override traffic signals to initiate a red light cycle for traffic on the near side of the intersection to stop thereby allowing the bus to enter into the regular lane of traffic. Queue jumps are one example of Traffic Signal Priority (TSP) technology.

Right-of-Way (ROW)
Property owned by a government agency used for the construction of public facilities like a roadway, railroad or a bridge. ROW can also include open or vacant land where infrastructure existed at one time (such as an abandoned railroad or streetcar line).

Rectangular Rapid Flash Beacon (RRFB)
A warning device at uncontrolled or midblock crossings, where pedestrians push a button to activate rapid flashing yellow LED lights to alert drivers to stop.

Regional Transportation Authority (RTA)
The RTA serves as the governing body which manages the public transportation service providers in the six-county (Cook, DuPage, Kane, Lake, McHenry, and Will) Chicago-area, including the Chicago Transit Authority (CTA), Metra, and Pace. Besides providing financial and management support for the transit agencies, RTA conducts long-range transportation studies and maintains several funding programs for planning transportation improvements in metropolitan Chicago.

Road Diet
A road diet reduces the amount of space for motor vehicles, either by eliminating through lanes or shrinking the width of lanes. The reclaimed space from a road diet is then re-allocated for other uses, such as turn lanes, bus lanes, pedestrian refuge islands, bike lanes, or more sidewalk space. Road diets often involve converting a four- or five-lane roadway into a three-lane street.

Roadway Capacity
The capacity of a roadway is defined as the maximum hourly rate at which vehicles can reasonably be expected to travel through an intersection or section of roadway during a given time period. Some factors having a primary influence on the capacity of an intersection or roadway segment are: the number and width of lanes, other geometric considerations (sight distance, approach grades, turning radii), vehicle mix, turning percentages and signal timings.

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 dredge 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.

Socioeconomic Data
United States Census data and/or employment data that are used in the transportation planning process to identify population, households, income levels, and areas of employment.

A stakeholder is anyone who could be affected by the project and has a stake in its outcome.

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 Tollway, CMAP, 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 2040 Regional Transportation Plan (GOTO 2040), 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.

Traffic Analysis Zone (TAZ)
A traffic analysis zone is a small geographic area, typically between .25 and 1 square mile, that is used in the travel demand forecasting process which projects future year traffic volumes. A TAZ contains socioeconomic data that is used to generate the future year traffic.

Traffic Control Device (TCD)
Traffic control devices (signals, stop and yield signs) are devices to control the speed and movement of traffic.

Transit Oriented Development (TOD)
Transit Oriented Development (TOD) is a planning and development approach that concentrates mixed-use development within rail transit station areas. This includes a range of integrated residential, retail, service and office uses. TODs are walkable areas of compact development.

Transit Signal Priority (TSP)
Transit Signal Priority (TSP) makes transit service more efficient and effective by giving transit vehicles more green time and les red time at traffic signals.

Transportation Demand Management (TDM)
A set of strategies that promote increased efficiency of the transportation system by reducing the incidence of single occupant vehicle travel.

Transportation Improvement Program (TIP)
A Transportation Improvement Program (TIP) is an agenda of surface transportation projects which includes all federally funded projects and regionally significant, non-federally funded projects programmed for implementation over a five year period. In the United States, MPOs are required to develop TIPs and update them accordingly as projects are added, dropped, changed, or completed. TIPs use spending, regulating, operating, management, and financial tools to help governments and the general public to track federal, state, and local funds dedicated to transportation improvements.

Transportation System Management (TSM)
Transportation system management optimizes the performance of existing infrastructure by implementing projects designed to conserve capacity and improve safety and reliability.

Vehicular Delay
The primary performance measure on interrupted flow facilities, especially at signalized intersections. For this element, average control delay is measured, which is expressed in seconds per vehicle. Control delay includes the time vehicles are slowing down approaching a traffic signal or stopped at the intersection.

Acronyms for Cook County LRTP

The evolution of transportation and environmental studies has generated a considerable number of acronyms. These have been created for the names of many Federal, State and County agencies, laws, studies, terms, etc. The following list identifies acronyms, which may be used in conjunction with this study:

Acronym Definition
AASHTO American Association of State Highway and Transportation Officials
ADA Americans with Disabilities Act
ADT Average Daily Traffic
APS Accessible Pedestrian Signal
ASC Adaptive Signal Control
ATA (ActiveTrans) Active Transportation Alliance
BMP Best Management Practices
BRT Bus-Rapid Transit
CACC Chicago Area Clean Cities Coalition
CAF Chicago Architecture Foundation
CAPS Chicago Alternative Policing Strategy
CCA Civic Consulting Alliance
CCAP Chicago Climate Action Plan
CCDOTHCook County Department of Transportation and Highways
CCT Chicago Community Trust
CDOT Chicago Department of Transportation
CDPH Chicago Department of Public Health
CDR Combined Design Report
CE Categorical Exclusion
CEQ Council on Environmental Quality
CFR Code of Federal Regulations
CMAP Chicago Metropolitan Agency for Planning
CMAQ Congestion Mitigation and Air Quality Improvement Program
CNT Center for Neighborhood Technology
CNU Congress for the New Urbanism
CPD Chicago Park District
CPS Chicago Public Schools
CSS Context Sensitive Solutions
CTA Chicago Transit Authority
DEIS Draft Environmental Impact Statement
DHED Department of Housing and Economic Development
DOI (United States) Department of Interior
EA Environmental Assessment
EIS Environmental Impact Statement
ELPC Environmental Law and Policy Center
EPA (United States) Environmental Protection Agency
ESA (Federal) Endangered Species Act
FEIS Final Environmental Impact Statement
FEMA Federal Emergency Management Agency
FHWA Federal Highway Administration
FIRM Flood Insurance Rate Map
FOIA Freedom of Information Act
FONSI Finding of No Significant Impact
FRA Federal Railroad Administration
FTA Federal Transit Administration
FWS (United States) Fish and Wildlife Service
GIS Geographic Information System
ICC Illinois Commerce Commission
IDNR Illinois Department of Natural Resources
IDOA Illinois Department of Agriculture
IDOT Illinois Department of Transportation
IEPA Illinois Environmental Protection Agency
IHPA Illinois Historic Preservation Agency
INHS Illinois Natural History Survey
INPC Illinois Nature Preserves Commission
ISGS Illinois State Geological Survey
ISWS Illinois State Water Survey
ITE Institute of Transportation Engineers
LAWCON Land and Water Conservation Fund (Act)
LOS Level of Service
LPI Leading Pedestrian Intervals
LTOR Left Turn on Red
MAP-21 Moving Ahead for Progress in the 21st Century
MBAC Mayor's Bicycle Advisory Council
MPC Metropolitan Planning Council
MPO Metropolitan Planning Organization
MUTCD Manual on Uniform Traffic Control Devices
NAAQS National Ambient Air Quality Standards
NEPA National Environmental Policy Act
NHPA National Historic Preservation Act
NHS National Highway System
NPDES National Pollutant Discharge Elimination System
NRCS Natural Resources Conservation Service
NRHP National Register of Historic Places
OEMC Office of Emergency Management and Communications
OUC Office of Underground Coordination
OWR Office of Water Resources (IDNR)
PHB Pedestrian Hybrid Beacon
PSI Preliminary Site Investigation
RCRA Resource Conservation and Recovery Act
ROD Record of Decision
ROW Right-of-Way
RRFB Rectangular Rapid Flash Beacon
RTA Regional Transportation Authority
RTOR Right Turn on Red
SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users
SHPO State Historic Preservation Officer
SIP Stakeholder Involvement Plan
SRA (IDOT) Strategic Regional Arterial
STP Surface Transportation Program
SWA Special Waste Assessment
TCD Traffic Control Device
TDM Travel Demand Management
TIP Transportation Improvement Program
TSM Transportation System Management
TSP Transit Signal Priority
URAA Uniform Relocation Assistance Act
USACOE United States Army Corps of Engineers
USDA United States Department of Agriculture
USDOT United States Department of Transportation
USEPA United States Environmental Protection Agency
USFWS United States Fish and Wildlife Service
USGS United States Geological Survey