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Glossary and Acronyms

The following presents definitions for a number of terms typically used during the development of a long range transportation plan in Illinois.


Access, Accessibility - The opportunity to reach a given end use within a certain time frame, or without being impeded by physical, social or economic barriers. Typically, accessibility is the extent to which transportation improvements make connections between geographic areas or portions of the region that were not previously well connected.

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.

Air Quality - The cleanliness of the air; including Co, NOX, particulates, etc., the fewer pollutants in the air, the better the air quality.

Alignment - The route that an improvement, such as a bus or light rail line, could take through a corridor.

Alternative - A feasible transportation improvement that is under consideration.

Americans with Disabilities Act of 1990 (ADA) - Federal Law that requires public facilities, including transportation services, to be fully accessible for persons with disabilities.

Amtrak - The nation's intercity passenger rail system. Amtrak is the brand name of the National Railroad Passenger Corporation, a quasi-governmental agency created in 1971.

Arterial - 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.

Autonomous Vehicle - An autonomous vehicle (driverless vehicle, self-driving vehicle, robotic vehicle) is a vehicle that is capable of sensing its environment and navigating without human input. Autonomous vehicles can detect surroundings using a variety of techniques such as radar, lidar, GPS, odometry, and computer vision.

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.

Bikeway - A generic term for any road, street, or 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 On To 2050 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.

Collector - 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.

Commuter Rail - High capacity public transportation systems consisting of electric or diesel propelled train sets usually operating in right-of-way at ground level or an embankment. Commuter rail typically operates between a central city and its suburbs with station spacing generally 2 - 5 miles apart.

Complete Streets Concept - 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.

Conformity - The process to assess the compliance of any transportation plan, program, or project with air quality control plans. The conformity process is defined by the Clean Air Act and related amendments.

Congested Vehicle Miles of Travel - This measure indicates how many vehicle miles are traveled over the threshold for congestion conditions. If there is no congestion, then Congested VMT would be zero, however if traffic builds beyond the limit for congestion, then this measure would report the difference, or the amount causing the congestion.

Congestion Management System (CMS) - A plan developed by a Transportation Management Area (TMA) that provides for effective management of new and existing transportation facilities through the use of travel demand reduction and operational management strategies.

Containerized Cargo - Cargo is commercial goods that are being transported. Containers are standard-size, metal boxes that carry cargo and can be moved between modes, like between a ship, railcar or truck. Container on Flatcar (COFC) and Trailer on Flatcar (TOFC) are containers or truck trailers that sit on and are transported by flatbed railcars.

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.

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.

Demographics - Descriptive characteristics of populations. Examples include age, race and ethnicity, gender, income, employment and household status.

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.

Destination - The place where a trip ends.

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.

Environmental Justice - An Executive Order requiring to the greatest extent possible allowed by law, administer and implement its federal programs, policies, and activities that affect human health or the environment so as to identify and avoid disproportionately high and adverse effects on minority and low-income populations.

Environmental Mitigation - Methods, strategies or actions to reduce the negative (direct, indirect and/or cumulative) effects of a transportation project on the environment.

Expressway/Freeway - A controlled-access, divided highway for through traffic. Intersections with other roads are separated by different road levels.

Fixing America's Surface Transportation (FAST) Act - The Fixing America's Surface Transportation (FAST) Act is a five-year, $305 billion surface transportation reauthorization bill. The FAST Act authorizes federal highway, highway safety, transit and rail programs from federal fiscal years 2016 through 2020. The FAST Act modestly increases overall national highway funding. For Illinois, the FAST Act delivers approximately $7.5 billion for highways over five years.

Federal Aviation Administration (FAA) - Division of the U.S. Department of Transportation that oversees and funds aviation planning and programs.

Federal Highway Administration (FHWA) - Division of the U.S. Department of Transportation that oversees and funds highway planning and programs.

Federal Railroad Administration (FRA) - Division of the U.S. Department of Transportation that oversees and funds railroad planning and programs.

Federal Transit Administration (FTA) - Division of the U.S. Department of Transportation that oversees and funds transit planning and programs.

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

Freeway/Expressway - A controlled-access, divided highway for through traffic. Intersections with other roads are separated by different road levels.

Freight - Commercial goods carried by a vehicle, usually a truck, plane, train or ship; also known as cargo.

Forecast - A calculation or estimate of future conditions.

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.

Heavy Rail Transit (HRT) - Public transportation system consisting of steel wheeled, high performance electric powered rail vehicles operating in train sets. HRT usually operates in a right-of-way that is fully grade separated (elevated, trench, or subway) and serves denser urban areas with station spacing generally 1 mile apart.

Highway - Term used to describe higher capacity roads; also includes rights of way, bridges, railroad crossings, tunnels, drainage structures, signs, guardrails, and protective structures in connection with highways.

Highway Operations - How a transportation network functions; highway maintenance and network performance activities such as snow plowing, traffic signal maintenance, etc. Techniques that influence how a network functions, for example, traffic signals and signs are operational activities that control traffic.

High Occupancy Toll (HOT) - High Occupancy Toll is a road pricing scheme that allows lower occupancy vehicles to gain access to High Occupancy Vehicle (HOV) Lanes by paying a toll.

High Occupancy Vehicle (HOV) - HOV is an acronym for High Occupancy Vehicle and is typically used in association with travel lanes dedicated to a vehicle with a specified number of occupants being 2 or greater.

Human Capital - The skills, competencies, and knowledge embodied in the ability to perform work that produces economic value.

Human Services Transportation Plan - A coordinated plan for transit service delivery developed with transportation and human service providers that addresses the needs of individuals with disabilities, older adults, and low-income individuals, and that prioritizes transportation services for funding and implementation.

Illinois Department of Transportation - The Illinois Department of Transportation has responsibility for planning, construction and maintenance of Illinois' extensive transportation network. This network encompasses highways, bridges, airports, public transit, and rail freight and rail passenger systems.

Impact Fee Advisory Committee - Committee overseeing development of DuPage County Impact Fee ordinance and fee schedule.

Infrastructure - A term connoting the physical underpinnings of society at large, including, but not limited to, roads, bridges, transit, water and waste systems, public housing, sidewalks, utility installations, parks, public buildings and communication networks.

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.

Intermodal - 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.

Intersection - 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 system of highways that connects the principal metropolitan areas, cities, and industrial centers of the United States. The Interstate System also connects the US to internationally significant routes in Mexico and Canada. The routes of the Interstate System are selected jointly by the state department of transportation for each state and the adjoining states, subject to the approval of the US Secretary of Transportation.

Land Use - Refers to how land and the structures (development) on it are used, i.e., commercial, residential, retail, industrial, etc.

Light Rail Transit (LRT) - High capacity public transportation systems consisting of steel wheeled electric powered rail vehicles operating in train sets. LRT can operate in right-of-way that is grade separated or can operate in mixed traffic (street running). Typically serves urban and dense suburban areas with station spacing generally 1 mile apart.

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.

Major Investment - A "high-type highway or transit improvement of substantial cost that is expected to have a significant effect on capacity, traffic, level of service or mode share at the transportation corridor or sub-area scale."

Managed Lanes - Highway facilities or a set of lanes where operational strategies are proactively implemented. These operational strategies can include pricing (tolls, congestion pricing), vehicle eligibility (carpools and buses), and/or access control (express or reversible lanes).

Metra - Metra is a commuter railroad in the Chicago metropolitan area that operates 241 stations on 11 different rail lines. It is the fourth busiest commuter rail system in the United States by ridership and the largest and busiest commuter rail system outside the New York City metropolitan area. There were 83.4 million passenger rides in 2014, 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 Statistical Area (MSA) - Census Bureau delineation for major metro areas in the U.S. Also includes standard (SMSA) and consolidated metropolitan statistical area (CMSA).

Mitigation - 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.

Mobility - The ability to move or be moved from place to place. Typically, mobility is the ease with which movement can occur between geographic areas or parts of the region.

Mode, Intermodal, Multimodal - Forms of transportation, such as personal motorized vehicle, public transit, bicycling and walking. Intermodal refers to the connections between modes, and multi-modal refers to the availability of transportation options within a system or corridor.

Multimodal - 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.

Network - A graphic and/or mathematical representation of multimodal paths in a transportation system.

Non-Motorized - Non-motorized transportation, also known as active transportation and human powered transportation, includes walking and bicycling, as well as small-wheeled transport (skates, skateboards, push scooters and hand carts) and wheelchair travel.

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.

Paratransit, Demand Responsive or Dial-a-Ride - A service generally provided for the disabled or elderly which provides trips in response to customer calls. Generally, not a scheduled fixed-route service.

Peak Period - The time period, usually in the morning and afternoon, when demand for transportation is high.

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.

Phase I Engineering - Phase I work can vary from a very minor type study to an in-depth investigation of corridors, alternative alignments and cross sections, different highway types, and other design features with consideration of social, economic, environmental, and engineering factors. In addition, safety, serviceability, and economy must be considered during project development. The Phase I study should clearly describe the need for the improvement and how to implement the improvement in a logical and organized manner.

Phase II - Phase II work includes design and plan preparation for a project. Work also includes land acquisition, utility relocations and agency agreements.

Phase III - Phase III is project construction.

Public Participation - The active and meaningful involvement of the public in the development of transportation plans and improvement programs.

Public Private Partnerships (P3) - A contractual agreement between a public agency (federal, state or local) and a private sector entity in which the skills and assets of each sector (public and private) are shared in delivering a service or facility for the use of the general public. Each party also shares the risks and rewards potential in the delivery of the service and/or facility.

Public Road - Any road or street under the jurisdiction of and maintained by a public authority and open to public traffic.

Public Transit (or Transportation) - Generally refers to passenger service provided to the general public along established routes with fixed or variable schedules at published fares. Related terms include transit, mass transit, public transportation or paratransit. Transit modes include commuter rail, heavy or light transit, bus, or other vehicles designated for commercial transportation of non-related persons.

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.

Quality of Life - A term used to describe the lifestyle conditions of an area. Conditions include the scale and depth of opportunities or choices in housing, employment, transportation, the natural environment, education, health care, and recreational and entertainment activities.

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.

Reimbursement - Many funding sources and grants operate on a reimbursement formula. This requires work to be performed before the funds are transferred to the recipient.

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 4(f) - Section 4(f) refers to the original section within the U.S. Department of Transportation Act of 1966 which established the requirement for consideration of park and recreational lands, wildlife and waterfowl refuges, and historic sites in transportation project development.

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.

Shared Services - The provision of a service is completed or contracted by one organization or governmental unit and utilized by multiple organizations. This shared cost provides a more cost effective implementation of services.

Signal Pre-emption - A system that allows traffic signals to be preempted by emergency vehicles.

Single Occupant Vehicle (SOV) - A SOV is a vehicle that carries only one occupant (the driver) to a destination.

Smart Corridor - A Smart Corridor utilizes technology to optimize the traffic flow on a roadway.

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.

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

Stakeholder Involvement - A process that will facilitate effective identification and understanding of the (SIP) concerns and values of all stakeholders as an integral part of the project development process. It includes a formal written plan explaining how public input and comments will be obtained.

Stakeholder Involvement Plan (SIP) - The SIP is a blueprint for defining methods and tools to educate and engage all stakeholders in the decision-making process for a project. The SIP provides the framework for achieving consensus and communicating the decision-making process between the general public, public agencies, and governmental officials to identify transportation solutions for the project.

Strategic Regional Arterial (SRA) - The Strategic Regional Arterial system is a network of approximately 1,500 miles of existing roads in northeastern Illinois. The SRA system 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.

Sustainability - Address present and future needs while not harming the natural resources and unique human-environmental systems, including air, water, land, energy, and human ecology and/or those of other sustainable systems, includes fiscal and organizational.

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.

Traffic Forecasting Model - The traffic model is used primarily for assessment of development impact related to the Impact Fee Program but has utility outside the program in terms of analyzing land use and development impacts on corridor and sub-area traffic system performance.

Transit - Generally refers to passenger service provided to the general public along established routes with fixed or variable schedules at published fares. Related terms include public transit, mass transit, public transportation or paratransit. Transit modes include commuter rail, heavy or light transit, bus, or other vehicles designated for commercial transportation of non-related persons.

Transit Dependent - Persons who must rely on public transit or paratransit services for most of their transportation. Typically refers to individuals without access to a personal vehicle.

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 less 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 Network Provider - A person that offers or provides a transportation network service.

Transportation Network Service - A prearranged transportation service offered or provided for compensation using an Internet-enabled application or digital platform to connect potential passengers with transportation network drivers. The term “transportation network service” does not include a “ridesharing arrangement” as that term is defined in section 2 of the Illinois Ridesharing Arrangements Act, codified at 625 ILCS 30/2.

Transportation Network Vehicle - Any vehicle used to provide a transportation network service.

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.

Travel Time - Customarily calculated as the time it takes to travel from "door-to- door." In transportation planning, the measures of travel time include time spent accessing, waiting, and transferring between vehicles as well as time spent traveling.

Urbanized Area - Area that contains a city of 50,000 or more population plus incorporated surrounding areas meeting set size or density criteria.

U.S. Department of Transportation (DOT) - The principal direct federal funding and regulating agency for transportation facilities and programs. FHWA and FTA and units of the US DOT.

Vehicle Hours of Travel (VHT) - The sum of time all vehicles spend traveling, calculated most typically over a 24-hour period. This statistic is most commonly summed over some area like county but can also be calculated for specific routes or trip purposes like work.

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

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.


The evolution of transportation and environmental studies has generated a 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
CCDOTH Cook County Department of Transportation and Highways
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
CRS Condition Rating System (pavement)
CSS Context Sensitive Solutions
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
HSIP Highway Safety Improvement Program
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 llinois Nature Preserves Commission
IPP Illinois Prairie Path
IRI International Roughness Index (pavement)
ITEP IIllinois Transportation Enhancement Program
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
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
PROWAG Public Right-of-Way Advisory Group
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
SHPO State Historic Preservation Officer
SIP Stakeholder Involvement Plan
SRA (IDOT) Strategic Regional Arterial
STP Surface Transportation Program
SWA Special Waste Assessment
TAP Transportation Action Plan
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