The IMPO’s website and posted documents often include acronyms and industry-specific terminology. You can search this list using the “Ctrl + F” function in your website browser or download the PDF.
Common Planning Terms used by the Indianapolis MPO
A
AADT (Annual Average Daily Traffic) – The total volume of vehicle traffic on a highway or road for a year divided by 365 days.
AC (Advance Construction) – A financing tool that allows local public agencies to accelerate transportation projects using non-federal funds while maintaining eligibility to be reimbursed with federal funds at a later date.
Access – This is the measure of how many jobs or essential destinations a person can reach in a reasonable amount of time. It can be measured for walking, biking, public transit, and driving.
Active Transportation – Transportation that is human-powered or low-powered mobility, such as biking, walking, or rolling. Active transportation directly replaces motor vehicle miles traveled, so these modes are effective at conserving fuel, reducing vehicle pollution, bridging the first- and last-mile gap, and improving individual and public health. Bicycles, electric bikes, wheelchairs, scooters, and walking are all considered active transportation. Transit is sometimes included as active transportation because the majority of trips to or from a bus stop are walked or the mobility devices listed above.
ADA (Americans with Disabilities Act) – A civil rights law that prohibits discrimination based on disability. The ADA mandates that when roads are constructed or altered, they must include accessible features like curb ramps, ensuring people with disabilities can safely navigate pedestrian crossings and sidewalks, effectively making public rights-of-way accessible to all individuals. This includes people with hearing, vision, cognitive, walking, self-care, or independent living difficulties.
Adaptive Traffic Signals – Traffic signal systems that adjust their timing based on real-time traffic conditions to improve flow.
ADT (Average Daily Traffic) – The average number of vehicles passing a specific point in a 24-hour period, often measured throughout a year. It is a standard measurement for vehicle traffic-load on a section of road and is used when making transportation planning decisions.
Affordable Housing – Housing units where the mortgage or rental cost does not exceed 30% of household income for households at, above, or below a defined percentage of the Area Median Income (AMI). aka: Attainable Housing
Air Pollution – Emissions from transportation uses contribute to smog and poor air quality, which has negative impacts on the health and welfare of U.S. citizens. Pollutants that contribute to poor air quality include ozone (O), particulate matter (PM), nitrogen oxides (NOx), and volatile organic compounds (VOCs).
Allocation – An administrative distribution of funds among the States, or among subunits in a metropolitan area, done for funds that do not have a statutory distribution requirement.
Allocation Goals – The Metropolitan Transportation Plan (MTP) sets goals for how much of the region’s funding should go to different types of projects. The MTP’s “resource allocation goals” are used for the distribution of IMPO-managed funds including allocations for Road + Road Geometry, Roadway Expansion, Intersection Improvements, Bridge Preservation, Bicycle & Pedestrian, and Transit projects.
AMI (Area Median Income) – The household income midpoint for a specific geography when lining incomes up from lowest to highest. Generally representative of the typical household income because it removes skewing from the absolute lowest or highest incomes.
Annual List of Obligated Projects – In accordance with Federal requirements, the MPO publishes its “Annual List of Obligated Projects” (ALOP) based on information provided by INDOT. The ALOP’s audience is the public, State, and Local officials, and it provides information regarding federal spending on transportation projects within the Indianapolis region, along with a progress report and disclosure of project delivery occurring over a shorter planning period of only one year.
Apportionment – Yearly funds allocated to each state by Congress to design and construct federal aid transportation projects.
ARIES (Automated Reporting Information Exchange System) – ARIES records are the official crash record repository for the State of Indiana.
Arterial Road – The functional classification is the grouping of highways, roads, and streets by the character of service they provide. Within this system, arterials are types of roads designed to carry high volumes of motorized traffic. Within the classification system, arterial roads are higher than “collector” streets.
Attainment Area – A geographic region where air quality meets or is better than the National Ambient Air Quality Standards (NAAQS) set by the EPA for a specific pollutant. Areas in compliance with standards for a pollutant are designated as attainment areas for that pollutant.
B
Bid / Letting – Public agencies may put projects “out to bid” meaning they allow private contractors to submit proposals to complete a project including the work and labor often with materials at a certain price per unit. The agency then selects a bidder’s proposal and enters into a contract to complete the work based on that proposal. This process is known as “letting” a project.
Big Data – Very large and complex datasets from various types of mobile network operators, navigation apps, public transportation usage data, and other transportation data sources that can be used to inform the region’s Travel Demand Model and other types of analysis to support land use policy, transportation policy, plans, and projects.
Bike/Bicycle and Pedestrian Projects – Projects dedicated to people walking, rolling, or biking including trails, bike lanes, safe routes to school, safety projects like sidewalk or sidewalk crossing improvements, and other projects focused on bikes and pedestrians.
Bridge Preservation – Rehabilitation projects to keep bridges in states of good repair.
Brownfield Development – Redevelopment of an abandoned or underutilized commercial or industrial site where the past use resulted in real or probable pollution of the soil or water resources on the site, requiring environmental remediation prior to reuse. The site is often already served by public or private utility companies.
BRT (Bus Rapid Transit) – Enhanced transit routes with features like dedicated bus lanes for all or part of a route, high-quality stations at limited intervals, traffic signal pre-emption, corridor branding, and frequent service.
C
Call for Projects – The call for projects is a process by which the IMPO’s Transportation Policy Committee selects projects to receive IMPO-managed funding. During the call-for-projects, local public agencies (typically cities, towns, counties, and transit organizations) choose projects to submit for consideration by completing a data-driven application and committing to locally fund a portion of the project cost. The IMPO then selects projects for funding based on the funding goals of the Metropolitan Transportation Plan (MTP) as adopted by the IMPO’s Transportation Policy Committee, federal eligibility requirements for different funding sources, and on their rank after the scoring process based on approved scoring criteria.
Capacity Expansion – Capacity expansion includes any project that makes room for more cars on the roads like adding lanes to existing roads or building entirely new roads.
Capital Improvements Program – Capital improvement programming is the scheduling of public physical improvements for a community over a certain period of time. The scheduling is based on a series of priorities according to the need, desire, or importance of such improvements and the community’s present and anticipated financial standing.
Capital Project – A major construction project or acquisition. This may apply to all transportation modes, for example, facilities for pedestrians and cyclists, purchasing buses, or maintaining, improving, and constructing roads and bridges.
Carryover – Federal funds which were not spent in a past fiscal year that can be used to pay for projects in future fiscal years.
CAA (Clean Air Act) – The Clean Air Act (1970) is the law that defines EPA’s responsibilities for protecting and improving the nation’s air quality and the stratospheric ozone layer. The last major change in the law, the Clean Air Act Amendments of 1990, was enacted by Congress in 1990. Legislation passed since then has made several minor changes.
C/B (Cost-Benefit) Analysis – A cost-benefit analysis endeavors to compare the monetary benefits of a project with the cost. Some approaches focus on one benefit (such as air quality impact) that can be easily measured. Other approaches expand to include other factors that may be harder to measure or focus on relative cost-effectiveness comparing projects against each other toward a series of goals instead of a specific goal.
CE (Construction Engineering) Phase – The CE phase begins on the day a Construction Contract is awarded. Tasks included in the CE phase include construction oversight and inspection, monitoring traffic control, monitoring environmental commitments, monitoring for a safe work environment, material testing/Quality Assurance Plan, documenting quantities and pay estimates, and record keeping.
Centerline miles – Centerline miles are a measurement of the total length of a road or highway, from start to finish. When calculating centerline miles, the number and width of lanes are not considered.
Central Indiana 9-county Airshed – A geographic region designated by the EPA that requires monitoring and reporting of air quality for certain pollutants. This airshed includes Boone, Hamilton, Hancock, Hendricks, Johnson, Madison, Marion, Morgan, and Shelby Counties.
CIRDA (Central Indiana Regional Development Authority) – An intergovernmental economic development alliance with members representing Central Indiana municipalities.
CIRTA (Central Indiana Regional Transportation Authority) – Created for the purpose of acquiring, improving, operating, maintaining, financing, and generally supporting a public transportation system that operates within Central Indiana. CIRTA jurisdiction includes Boone, Delaware, Hamilton, Hancock, Hendricks, Johnson, Madison, Marion, Morgan, and Shelby Counties.
CMAQ (Congestion Mitigation and Air Quality) Program – The Congestion Mitigation and Air Quality Program provides funds for projects and activities that reduce congestion and improve air quality, often focused on non-automotive or off-peak travel solutions.
CN (Construction) Phase – The construction phase is the implementation phase of a project including the labor and materials to construct a project.
COA (Comprehensive Operational Analysis) – A process that examines and evaluates a transit system to determine where improvements can be made to make transit operations more effective and efficient across the network.
Collector Street – Within the functional classification system, a collector is a street or highway that provides for traffic movement between major streets and local streets. It is a road intended to collect traffic from local streets and land-access roads.
Complete Streets – Complete Streets is an approach to planning, designing, building, operating, and maintaining streets that enables safe access for all people who need to use them, including people of all ages and abilities and all modes including walking, biking, and rolling, driving vehicles, and using transit.
Comprehensive plan – Comprehensive plans in Indiana are legal documents that outline a community’s vision and goals for the future typically 20 years out. They are intended to guide decision-making on matters such as land use, development, transportation, and public works. In Indiana, comprehensive plans must include a statement of objectives for the jurisdiction’s future development, a statement of policy for land use development, and a statement of policy for the development of public ways, places, lands, structures, and utilities.
Contingency – A contingency is an amount of money set aside to cover any unexpected costs that can arise throughout a construction project.
Conformity – Process to assess the compliance of any transportation plan, program or project with air quality implementation plans. The conformity process is defined by the Clean Air Act and subsequent guidance.
Countermeasures – Treatments or design interventions that are proven to improve safety and reduce the risk of crashes on roads or at intersections or crossings. They range from high to low cost, and from major construction (like roundabouts and road diets) to signage, signal adjustments, enforcement activities, and more.
Curb Management – Planning and allocation of curb space to accommodate different uses, such as deliveries, parking, ride-hailing pickups, and bike lanes.
D
Demand Management – A set of strategies that promote increased efficiency of the transportation system by influencing individual travel behavior by maximizing traveler choices.
Density – Number of housing units per land area on a site, usually measured in a number of units per acre.
Discretionary Funds – Any funds whose distribution is not automatically allocated by a formula. Decisions on the distribution of discretionary funds are usually made by an agency or person on the basis of that agency’s or person’s choice or judgment and in accordance with criteria set out in law or regulations.
DMD (Indianapolis Department of Metropolitan Development) – The department that oversees community planning and zoning in Indianapolis-Marion County.
DOT (Department of Transportation) – An agency or division within a unit of government responsible with overseeing and structure that unit’s transportation system. May exist at federal, state, or local levels. The “DOT” abbreviation is often used in reference to the United States (federal) DOT.
DPW (Department of Public Works) – An agency responsible for the implementation of transportation projects in a municipality.
DVMT (Daily Vehicle Miles Traveled) – A measure of the total traffic on a road, calculated by multiplying the average daily traffic count by the length of the road.
E
Easement – Easements allow individuals, corporations, governments, or the public to use a piece of property belonging to a separate individual or entity for a specific purpose. For example, utility companies commonly use utility easements to create or maintain power lines or cables on private property.
EPA (Environmental Protection Agency) – A United States federal agency tasked with protecting human health and the environment by developing and enforcing regulations, providing grants, studying environmental issues, establishing partnerships, and providing education and information about the environment.
EJ (Environmental Justice) – A 1994 Presidential Executive Order to assure that governmental services and benefits allow for meaningful participation and are fairly distributed to avoid discrimination. The Executive Order was rescinded in 2025.
Evaluation Criteria – A process developed as part of the programming process for evaluating the relative merits of projects.
Exempt project – Projects that are exempt from requiring an air quality conformity determination. Exempt projects include transportation facilities that are not expected to have a “regionally significant” impact on travel demand and movement or significantly increase transportation pollutants.
F
Federal Fiscal Year – The federal government’s / U.S. Congress fiscal year runs from October 1 of one calendar year through September 30 of the next. The federal fiscal year (FY) is designated by the calendar year in which it ends (e.g. FY 2026 runs from Oct 1, 2025 – Sep 30, 2026).
Federal-aid Highways – Those highways eligible for assistance under Title 12 of the United States Code (U.S.C.), except those functionally classified as local or rural minor collector. These roads are not always “highways” in the popular usage of the word but include many types of roads.
Federal-aid Project – Federal aid projects are local public agency projects that use federal funding. These projects must follow federal standards (NEPA, etc.). Local public agencies own and operate 3/4 of the nation’s roadway network.
FFE (Federal Funds Exchange) Program – In August of 2020, the Indianapolis Metropolitan Planning Organization (IMPO) signed an agreement with the Indiana Department of Transportation (INDOT) to exchange the IMPO’s annual allocation of Federal transportation program funds for State funds to fund regionally significant transportation projects in the Indianapolis Regional Transportation Improvement Program (TIP).
FHWA (Federal Highway Administration) – A division of the U.S. Department of Transportation which executes the highway-oriented provisions of the federal transportation program through the state departments of transportation and metropolitan planning organizations. The FHWA administers federal funding for highway planning and programming. In cooperation with the Federal Transit Administration and the Environmental Protection Agency, the FHWA prepares and issues regulations as required by law, monitors compliance, provides support for the technical developments necessary to implement the federal transportation authorizing act.
First-Last Mile – Refers to the beginning or end segments of a trip, particularly for transit users, highlighting the gap between home or work and access to public transportation.
Fiscally Constrained – Both the Metropolitan Transportation Plan (MTP) and the Transportation Improvement Program (TIP) are required to be based on financial plans that are fiscally constrained, which means that these documents can only contain projects for which it is determined that funding sources are reasonably available over the life of the plan/program to pay for both the capital and operating cost of the proposed improvements.
Floodplain – The Federal Emergency Management Administration (FEMA) defines a floodplain as any land area susceptible to being inundated by floodwaters from any source. This can include coastal areas impacted by storm surge, land along a river or bayou that is flooded when that waterway rises out of its banks, or low-lying land that fills with water when it rains. Flooding occurs in a wide range of landscapes due to rainfall or storm surge.
Formula Funds – Funds distributed or apportioned to qualifying recipients based on formulas described in law or regulations. This is different than a discretionary grant program where eligible applicants may competitively seek funding.
FTA (Federal Transit Administration) – A division of the U.S. Dept. of Transportation responsible for administering federal public transportation funds and programs. This ranges from planning and operating assistance to the purchase of buses, trains, and building of transit stations.
Functional Classification System – The Functional Classification system groups roadways based on their purpose in the overall roadway system. Every public road is classified as either local, collector, or arterial depending on how each road serves the overall system. The Functional Classification is used in setting standards for roadway design, determining eligibility for federal-aid program funding, and monitoring roadway performance by transportation planning agencies. The IMPO primarily references the Indiana Department of Transportation (INDOT) functional classification map and definitions.
FY (Fiscal Year) – A 12-month period for agency budgets. Fiscal years ranges can vary (see “State Fiscal Year” and “Federal Fiscal Year”). The IMPO budgets to a calendar fiscal year of January 1 to December 31.
G
GIS (Geographic Information System) – A computer-based data management tool used for mapping, storing, retrieving, analyzing, and displaying geographic data. GIS uses geographic data, also known as spatial or geospatial data, to create maps that help users visualize and understand patterns and relationships.
Grayfield Development – Redevelopment/infill on previously developed land, often already served by public or private utilities.
Greenfield Development – Development on previously undeveloped land, rarely served by pre-existing public or private utilities.
Greenways – Networks of trails, paths, or corridors designed for human-powered transportation or electric micromobility devices, often integrated with natural landscapes.
H
Headway – The length of time at a stop between buses following the same route.
Heat Island – Unshaded, heat-absorbing surfaces such as asphalt, concrete, and other paving materials can increase ambient air temperatures. This effect can increase material maintenance costs and require more energy for cooling.
HIN (High Injury Network) – Identifies roadway corridors with the highest frequencies of crashes resulting in incapacitating injuries and fatalities within the Metropolitan Planning Area. A HIN can be used to prioritize safety investments and other strategies to make progress toward regional safety goals.
H+T (Housing and Transportation) Affordability Index – Indicates the combined impact of housing and transportation costs on households in a defined area.
HSIP (Highway Safety Improvement Program) – Funds used to implement proven safety projects such as roundabouts, traffic calming to reduce vehicle speeds, pedestrian infrastructure to make crossing the street safer, guardrails, signage, or safe routes to school.
I
IDEM (Indiana Department of Environmental Management) – State department responsible for completing and carrying out environmental policies and requirements. Oversees air quality conformity and State Implementation Plans for air quality nonattainment areas.
Impermeable Surface – Surfaces that water cannot penetrate, causing rain or runoff to flow over the surface rather than soak into the ground. Too many impermeable surfaces without sufficient alternative drainage solutions can lead to flooding in the immediate area or downstream.
IMPO (Indianapolis Metropolitan Planning Organization) – Federally- and state-designated MPO for the Central Indiana region of Boone, Hamilton, Hancock, Hendricks, Johnson, Marion, Morgan, and Shelby Counties.
Induced Demand – The concept that as transportation capacity is increased (such as adding new lanes to a roadway), more people will choose to use that roadway, which over time leads to increased traffic that can negate the originally intended congestion relief.
IndyGo – The brand name for the Indianapolis Public Transportation Corporation.
INDOT (Indiana Department of Transportation) – The multi-modal transportation agency for the State of Indiana which builds projects, maintains the state and interstate highway systems, and administers transportation funds.
Infill Development – Development on vacant or underutilized land within already built-up urban areas.
Infrastructure – The physical above and below-ground systems that serve mobility and societal functions. Transportation infrastructure includes roads, curbs, sidewalks, trails, bridges, railways, airports, and more. Utility infrastructure includes water/waste/stormwater pipes, electrical and communication wires, and more.
ITS (Intelligent Transportation System) – The integrated application of various technologies and management strategies to provide traveler information or connected communications to increase the safety and efficiency of the surface transportation system. Examples of ITS include signal timing, electronic message boards, real-time travel information, and automated vehicle locators (used by transit systems).
ITDM (Indianapolis Travel Demand Model) – A model that is used to forecast future automobile and transit use on the transportation system based on proposed improvements, project air quality impacts, and outputs a wide variety of measures useful when evaluating transportation policy, plans, and projects.
IPTC (Indianapolis Public Transportation Corporation) – The agency responsible for public transportation in the City of Indianapolis, Marion County, and other contributing municipalities.
L
Land Use – A term used to describe the way humans classify and use space for housing, commerce, industry, agriculture, transportation, recreation, or conservation.
Lane Miles – The total length of a road or highway, multiplied by the number of lanes. For example, a two-mile long road with four lanes has eight lane miles.
Letting – When a project goes out for bid for construction. Companies will bid on the construction contract to complete the project on behalf of a local public agency. Lettings must be advertised in advance and state lettings are only available on certain dates.
LOS (Level of Service) – An assessment of a road’s operating condition for a specified mode of transportation, generally described using a scale of A (little congestion) to F (severe congestion), often prioritizing travel speed. Alternatives to LOS include evaluating vehicle miles traveled, “person throughput” which evaluates the number of people moving through a corridor regardless of mode of transportation, and accessibility metrics measuring the time or travel distance between residents and essential services and jobs.
LPA (Local Public Agency) – A city, county, township, municipality, or other political subdivision that is empowered to cooperate with the State transportation department in highway matters.
M
Maintenance Area – An area that was previously designated as nonattainment for a pollutant but has since been redesignated to attainment and is required to maintain air quality reporting through an approved maintenance plan.
Market-Rate Housing – Housing rented or sold at market prices without income restrictions.
MCCOG (Madison County Council of Governments) – The Federally- and State-designated MPO for Madison County.
Micromobility – A category of transportation modes involving small, lightweight vehicles like electric scooters, bikes, or skateboards, typically used for short trips.
Missing Middle Housing – Moderate-density housing types on a scale between single-family homes and large apartment buildings.
Mode – A specific form of transportation, such as automobile, subway, bus, rail, bike, or air.
Mode share or mode split – The percentage of a population that utilizes a specific transportation mode to complete a trip.
MPO (Metropolitan Planning Organization) – A Federally-designated regional transportation planning body identified for any area containing over 50,000 residents. MPOs distribute planning funding for transportation and land use studies and construction funding for transportation projects.
MPA (Metropolitan Planning Area) – The geographic area in which the metropolitan transportation planning process as required by 23 USC 134 and section 8 of the Federal Transit Act must be carried out. The MPA includes the urbanized area and the area expected to be urban in 20 years. The Central Indiana MPA includes all of Marion County and portions of Boone, Hamilton, Hancock, Hendricks, Johnson, Morgan, and Shelby Counties.
MSA (Metropolitan Statistical Area) – A core area containing a substantial population nucleus, together with adjacent communities having a high degree of economic and social integration with that core.
MTP (Metropolitan Transportation Plan) – The official intermodal transportation plan that is developed and adopted through the metropolitan transportation planning process for the metropolitan planning area.
Multimodal – The availability of transportation options using different modes within a system or corridor.
N
NAAQS (National Ambient Air Quality Standards) – Federal standards that set allowable concentrations and exposure limits for various pollutants. The EPA developed the standards in response to a requirement of the CAA.
NEPA (National Environmental Policy Act) – A law that requires federal agencies to evaluate the environmental impact of any proposed federally funded infrastructure project. NEPA’s requirements include (human and ecological) environmental review, public involvement, and other documentation.
Nonattainment Area – A geographic region where air quality does not meet the National Ambient Air Quality Standards (NAAQS) set by the EPA for a specific pollutant. These areas fail to meet federal standards and are subject to stricter state and federal control measures to improve air quality.
Non-exempt project – Projects that are not exempt from, and therefore require, air quality conformity determinations, regardless of how they are funded. Non-exempt projects include transportation facilities that are expected to have a “regionally significant” impact on travel demand and movement or may significantly increase transportation pollutants, such as a new interstate interchange or widening a major roadway.
O
Obligated Funds – Funding that has been approved and set-aside for a particular project. The funding is usually reserved for several years as long as the project it was reserved for is still active.
Onboard Survey – Surveys taken aboard a transit system typically to collect data for scheduling and operations planning, long-range planning and design, and performance analysis. Surveys typically ask transit users about the trips they take on transit, and demographic information about the transit user and their household.
Operating Costs – Expenses associated with the general, day to day costs of running transportation systems. For transit, operating costs include fuel, salaries, and replacement parts. For roads, operating costs involve maintaining pavement, filling potholes, and paying workers salaries.
Orphan Area – A specific subset of maintenance or nonattainment areas originally designated under an older NAAQS (e.g. 1997 ozone standard), then redesignated or maintained as attainment under a newer standard (e.g. 2008 ozone), especially after the earlier standard was revoked. Per court rulings, these “orphans” must meet residual obligations for transportation conformity reporting and approval. The Central Indiana 9-county airshed is designated as an Orphan Area.
P
Paratransit – Types of passenger transportation that are more flexible than conventional fixed-route transit but more structured than the use of private automobiles. Paratransit is a broad term that may be used to describe any means of shared ride transportation other than fixed route mass transit services. Paratransit services usually use smaller vehicles (less than 25 passengers) and provide advance-reservation, demand-responsive service that is either curb-to-curb or door-to-door. Paratransit services that are provided to accommodate passengers with disabilities who are unable to use fixed route service and that meet specific service equivalency tests are called ADA-complementary paratransit services.
Parking Mandates – Parking mandates are a form of land use regulation or zoning that requires a specific amount of parking to be provided for a land use to serve residents, employees, or visitors.
Pavement Preservation – Pavement preservation includes a wide variety of road projects such as reconstruction, rehabilitation, resurfacing, restoration, and preservation.
Peak Period – Time periods, usually coinciding with the commute to and from work, when transportation demand is heaviest.
Permeable – Permeable surfaces (also known as porous or pervious surfaces) allow water to percolate into the soil unlike concrete and asphalt.
PMs (Performance Measures) – Goals or “targets” that are set for various transportation facility performance metrics. Data associated with PMs is tracked and compared to the targets to determine the area’s progress toward reaching the target. PM focus areas include Safety (PM-1), Infrastructure Condition (PM2), Congestion Reduction (PM-3), System Reliability (PM-3), Freight Movement and Economic Vitality (PM3), Environmental Well-being, and Reduced Project Delivery Delay.
PL (Planning Funds) – The principal source of funding for carrying out the MPO transportation planning process. These federal funds may not be used to build projects but may be used for identifying needs and writing plans to address those needs.
Procurement – Procurement refers to the process by which public authorities, such as government departments or local authorities, purchase work, goods or services from companies. Procurement practices are regulated at both the state and federal levels. During procurement, public agencies typically publicly post their needs and allow private organizations to submit bids to fulfill those needs with a goal of open and fair competition.
Programming – A process required under Federal statute and regulations (23 CFR Part 450) for developing a staged, prioritized, fiscally constrained, multi-year, intermodal program of projects for funding, consistent with the metropolitan transportation plan. States and local laws may also impose programming requirements that have to be coordinated with the federal effort.
PROWAG (Public Right-of-Way Accessibility Guidelines) – Guidelines that ensure pedestrian facilities are accessible to people with disabilities. The guidelines apply to sidewalks, crosswalks, signals, and other pedestrian facilities.
PSCi (Proven Safety Countermeasures Initiative) – This FHWA initiative is a collection of countermeasures and strategies, backed by data, that are effective in reducing roadway fatalities and serious injuries on roadways. Each countermeasure addresses at least one safety focus area – speed management, intersections, roadway departures, or pedestrians/bicyclists – while others are crosscutting strategies that address multiple safety focus areas.
Public Participation/Engagement – An integral part of the transportation process which helps to ensure that decisions are made in consideration of and to benefit public needs and preferences. Early and continuous public involvement brings diverse viewpoints and values into the decision-making process. This process enables agencies to make better-informed decisions through collaborative efforts and builds mutual understanding and trust between the agencies and the public they serve. Successful public participation/engagement is a continuous process, consisting of a series of activities and actions to both inform the public and stakeholders and to obtain input from them which influences decisions that affect their lives.
R
Regionally Significant – A transportation project (other than an exempt project) that is on a facility that serves regional transportation needs and would normally be included in the modeling of a metropolitan area’s transportation network. These projects often significantly change the capacity of the transportation facility, such as adding travel lanes to an arterial roadway or creating a new roadway, or creating new fixed transit routes.
Reverse Commuting – Movement in a direction opposite the main flow of traffic, such as from the central city to a suburb during the morning peak period.
RFI (Red Flag Investigation) – A quantitative analysis of infrastructure, water, hazardous materials, historical features, and other data near a proposed transportation project.
Ridematch Program – A program that facilitates the formation of carpools and vanpool, usually for work trips. A database is maintained for the ride times, origins, destinations and driver/rider preferences of users and potential users.
Rideshare/Ride-hailing – Using a mobile app to match passengers with drivers who use their personal vehicles to provide on-demand rides.
Road Diet – A road diet is a road reconfiguration to reduce or narrow driving lanes, or add curb extensions, bulb-outs, bike lanes, pedestrian medians, landscaping, and other interventions to improve safety. The resulting benefits can include crash reduction, improved access by all road users, and creating a street that is more pleasant to use, better integrating the road into the neighborhood.
ROW (Right-of-Way) – A type of easement that allows an individual or entity access to move through the property. In transportation, ROW typically refers to the land owned by a government agency and generally used for the mobility of goods and people via roads, alleys, sidewalks, and other facilities. ROW may include undeveloped land adjacent to transportation facilities.
RSA (Road Safety Audit) – The formal safety performance examination of an existing or future road or intersection by an independent, multidisciplinary team. It qualitatively estimates and reports on potential road safety issues and identifies opportunities for improvements in safety for all road users.
S
Safe Systems Approach – A paradigm to address roadway safety via a holistic and comprehensive approach that provides a guiding framework to make places safer for people. The Safe Systems Approach emphasizes that Death and Serious Injuries are Unacceptable; Humans Make Mistakes; Humans Are Vulnerable; Responsibility is Shared by all individuals and stakeholder entities; Safety is Proactive; and Redundancy is Crucial. The objectives are Safer People; Safer Roads; Safer Vehicles; Safer Speeds, and Post-Crash Care.
SOV (Single Occupancy Vehicle) – A passenger vehicle that is designed to carry multiple people but is observed as carrying only one.
SRTS (Safe Routes to School) – A program that promotes walking and bicycling to school through infrastructure improvements, enforcement tools, safety education, and incentives to encourage walking and bicycling to school. SRTS initiatives improve safety and levels of physical activity for students.
State Fiscal Year – The state’s fiscal year runs from July 1 of one calendar year to June 30 of the next calendar year. The state fiscal year (FY) is designated by the calendar year in which it ends (e.g. FY 2026 runs from Jul 1, 2025 – Jun 30, 2026; also sometimes noted as FY 2025-2026).
STBG (Surface Transportation Block Grant) – The largest and most flexible source of federal funding for MPOs. These funds may be used for road, transit, bike and pedestrian construction projects, carpool programs, planning activities, and many other project types.
STIP (Statewide Transportation Improvement Program) – A staged, multiyear, statewide intermodal program of transportation projects which is consistent with the statewide transportation plan and planning processes and metropolitan plans, TIPs and processes.
T
Tactical Urbanism – An approach to neighborhood-building and street activation using short-term, low-cost, and scalable interventions and policies, often on roadways where there are real or perceived transportation safety concerns. Project examples include temporary bike lanes, pop-up bus shelters, temporarily painted crosswalks, and more.
Tax Abatement – Temporary reduction or forgiveness of property taxes to support development.
TA (Transportation Alternatives) – Set-aside funding from the Surface Transportation Block Grant (STBG) Program that provides funding for a variety of generally smaller-scale transportation projects including pedestrian and bicycle facilities, trails, safe routes to schools, community improvements and environmental mitigation.
TDM (Travel Demand Management) – Strategies, policies, and incentives designed to maximize traveler choices and optimize the efficiency of transportation networks. TDM often focuses on reducing congestion, such as changing the direction of roadway lanes depending on peak hours, or on policies to decrease single occupancy vehicles on the road by increasing the use of transit, ridesharing, walking, biking, or telework.
TIF (Tax Increment Financing) – A financing tool where future increases in property tax revenue within a defined area are used to help fund development in that area.
TIM (Traffic Incident Management) – Coordinated efforts to detect, respond to, and clear traffic incidents (such as crashes) to minimize their impact on congestion or secondary incidents.
TIP (Transportation Improvement Program) – A staged, prioritized, multi-year, intermodal program of transportation projects, prepared in each metropolitan area, which is consistent with that area’s metropolitan transportation plan. Each metropolitan TIP is incorporated in its entirety into the STIP.
TIP Amendment – Significant changes to the TIP that require an opportunity for public review and comment and require approval by the IMPO’s Transportation Policy Committee at a public hearing. This often includes adding new projects, deleting projects, or significant cost changes.
TIP Modification – Minor changes to projects or the TIP that do not require the IMPO’s Transportation Policy Committee’s approval or public review. These include but are not limited to general editorial corrections and changes to projects that do not involve a significant change in the use of IMPO funds such as minor cost increases, moving fiscal years within the active years of the current TIP, or minor scope changes that do not change the overall project impact or transportation conformity.
Title VI – Part of the Civil Rights Act of 1964, prohibits discrimination in any program receiving federal assistance.
TOD (Transit-Oriented Development) – Land development that takes place near high-capacity fixed transit stations. TOD often includes a mixture of housing, office, retail and/or other amenities integrated into a walkable environment.
Traffic Calming – Traffic calming is a set of design interventions aimed at slowing or diverting car traffic to reduce the chance of crashes and improve safety for all road users. Examples may include speed bumps, narrowing lanes, chicanes, or raised intersections.
Transit Capital Project – Construction projects such as bus stops or bus lane infrastructure, or purchasing buses themselves. It may also include other programs including carpool air quality programs.
Transportation Affordability – A household’s ability to cover travel expenses necessary for accessing goods and activities while staying within budget constraints. Experts suggest that transportation expenses should not exceed 15% of a household’s budget, and transportation + housing expenses should not exceed 45%.
Transportation Conformity – Transportation conformity is a regulatory process under the Clean Air Act that ensures federally funded or approved highway and transit projects are aligned with state air quality goals. The Indianapolis Travel Demand Model (ITDM) is used to monitor air quality for Ozone pollutants in Central Indiana.
Transportation Policy Committee – A Board with equal voting representation from IMPO member municipalities, counties, and transportation agencies. The Policy Committee meets every other month to discuss policy and projects, advise IMPO staff, and approve Plans, Programs, and related documents.
Transportation Technical Committee – A Board with equal voting representation from IMPO member municipalities, counties, and transportation agencies. The Technical Committee meets every other month to discuss policy and projects, advise IMPO staff, and vote on approval recommendations for Plans, Programs, and related documents. Votes taken by the Technical Committee are advisory to the Policy Committee.
Travel Time Reliability – The consistency and predictability of travel times on a given route over a period of time.
TrOD (Trail-Oriented Development) – Development along or near public trails or greenways, often a compact development pattern that is mixed-use, residential, and/or commercial, is walkable and human-scaled, and creates vibrant places that promote active modes of transportation and recreation.
U
UA (Urbanized Area) – A statistical geographic entity delineated by the Census Bureau, consisting of densely settled census tracts and blocks and adjacent densely settled territory that together contain at least 50,000 people.
UPWP (Unified Planning Work Program) – A core guiding document for the IMPO, which includes the IMPO’s mission, list of projects and tasks for the upcoming year, and the proposed budget for each task. It is updated annually and approved by the IMPO Transportation Policy Committee.
V
VHD (Vehicle Hours of Delay) – This is a travel time metric that reflects the difference between free-flow and congested travel time. This is primarily an output of the Indianapolis Travel Demand Model and is used to evaluate projects and congestion.
Vision Zero – A strategy to eliminate all travel-related deaths and serious injuries. Vision Zero emphasizes a Safe Systems approach, which acknowledges that people make mistakes and focuses on influencing system-wide practices, policies, responses, and urban design to lessen the frequency and severity of crashes.
VMT (Vehicle Miles Traveled) – The total number of miles driven by all vehicles within a given time period and geographic area, used by regional transportation and environmental agencies for planning purposes.
VRU (Vulnerable Road User) – People walking, people biking, and people using mobility devices such as wheelchairs. In the event of a crash, vulnerable road users have little to no protection from crash forces and are disproportionately injured or killed.
W
Walkability – A measure of how friendly an area is to walking, considering factors like scale, connectivity, safety, accessibility, and presence of pedestrian infrastructure.