TDM Encyclopedia

Victoria Transport Policy Institute


Updated 15 May 2014

This chapter provides definitions of terms related to Transportation Demand Management.


Accessibility: The ability to obtain desired goods, services and activities.


Active Transportation (also known as Nonmotorized Transportation and Human Powered Transportation) includes Walking, Bicycling, Small-Wheeled Transport (skates, skateboards, push scooters and hand carts) and Wheelchair travel.


Automobile Dependency: Transportation and land use patterns that result in high levels of automobile use and limited transportation alternatives. In this case, “automobile” includes cars, vans, light trucks, SUVs and motorcycles.


Automobility: Mobility by automobile.


Busways: Special lanes dedicated to transit buses, often incorporating other features to insure high quality transit service.


Charrette: A community design exercise that involves many people.


Complete Streetsrefers to roadway design and operating practices intended to safely accommodate diverse users and activities including pedestrians, cyclists, motorists, public transport users, people with disabilities, plus adjacent businesses and residents.


Congestion Pricing: Road pricing that varies with the level of traffic on a congested roadway. Congestion pricing is intended to allocate roadway space efficiently.


Cordon Pricing: Tolls charged for entering a particular area (a “cordon”), such as a downtown.


Cost: Resources used to produce a good or service, which may include money, time, materials, land or even risk and discomfort. Costs can be categorized in several ways:


·         Some costs are fixed (not related to consumption, such as vehicle registration fees and residential parking), while others are variable (directly increases with consumption, such as fuel and road tolls).


·         Some costs are internal (borne directly by the user of a good, such as transit fares and vehicle operating costs), while others are external (borne by others, or by users indirectly and not related to their consumption, such as pollution emissions and general taxes used to fund transportation services).


·         Some costs are market (commonly traded with money in a competitive market, such as vehicles and fuel), while others are nonmarket (not commonly traded in a market, such as crash risk and air quality).


Demand amount and type of travel people would choose under specific price and quality conditions.


Differential Pricing (also known as Variable Pricing): User charges that vary by factors such as vehicle type, vehicle occupancy, time of use, congestion level, facility location, air quality impact, or other factors.


Distance-Based Charges: These are fees charged for using a vehicle is based on the vehicle miles traveled (VMT) in a jurisdiction. They can include distance-based road user charges, emission charges, and insurance charges.


Dynamic Pricing: This refers to congestion pricing that reflects real-time congestion levels, as opposed to variable pricing that follows a fixed schedule.


Elasticity of Demand: A measure of the sensitivity of demand for a commodity to a change in its price. It equals the percentage change in consumption of the commodity that results from a one-percent change in its price. The greater the elasticity, the more price-sensitive the demand for the commodity. Price elasticities are an important indicator of the effects of pricing strategies.


Electronic Road Pricing: This refers to various electronic systems that collect vehicle tolls, which can reduce or eliminate the need for tollbooths and for vehicles to stop.


Emission Charges: Vehicle charges that vary based on emission rates.


Generated Traffic: Additional vehicle trips on a particular roadway or area that occur when roadway capacity is increased or travel conditions are improved, due to latent demand (additional trips that travelers would make if traffic conditions were improved). A portion of generated traffic often consists of induced travel, that is, an increase in total vehicle mileage (which excludes travel shifted from other times and routes).


GPS-Based Pricing: This involves road pricing based on the location and time that a vehicle is driven, using GPS (Global Positioning System) technology. It is a subcategory of distance-based charges.


High-Occupancy Vehicle (HOV): a passenger vehicle carrying more than a specified minimum number of passengers. HOVs include carpools, vanpools, and buses. HOV requirements are often indicated as 3+ (three or more passengers required) or 4+ (four or more passengers required).


HOV Lane: This is a traffic lane limited to carrying high occupancy vehicles (HOVs) and certain other qualified vehicles.


HOT Lanes (High Occupancy Toll Lanes): HOV facilities that allow lower occupancy vehicles, such as solo drivers, to use the facility if they pay a toll. This offers users three options: drive alone on an unpriced but congested general purpose lane, drive alone and pay to use a less congested lane, or rideshare (carpool, vanpool or ride transit) to use a less congested lane without any additional fee.


Freight Lane: A facility or lane restricted to authorized freight vehicles.


Grade Separated: Paths, special lanes, freeways, transit and rail lines that are completely separated from regular roadways and so are not delayed by cross-streets or roadway congestion.


Linked/Unlinked Trip: An unlinked trip is a passenger trip make on a single vehicle, such as a single automobile or bus ride. A linked trip is a person’s entire trip between an origin and destination, which may involve transferring between vehicles (e.g., Park & Ride or bus and rail transit), or multiple stops, such as stopping at a daycare center or store along a commute trip.


Managed Lane: A lane which is restricted to particular types of vehicles provide improved travel conditions to eligible users. Eligibility can be based on the number of people in the vehicle, the type of vehicle, users who are willing to pay a toll, or other criteria. Examples include HOV lanes, HOT lanes, freight lanes, and Value Priced lanes.


Market Distortions: Market conditions that violate basic market principles such as consumer choice, cost-based pricing or economic neutrality.


Motor Vehicle Fuel Tax: Taxes on motor vehicle fuels, which are usually considered a road user fee.


Mobility: The movement of people and goods.


Mobility Management (Also called Transportation Demand Management): Various strategies that change travel behavior (how, when and where people travel) in order to increase transport system efficiency and achieve specific objectives such as reduced traffic congestion, road and parking cost savings, increased safety, improved mobility for non-drivers, energy conservation and pollution emission reductions.


Multi-Modal Level-of-Service Indicators evaluate the quality of various transport modes from a users perspective, taking into account convenience, comfort and security.


Nonmotorized Transportation (also known as Active Transportation and Human Powered Transportation) includes Walking, Bicycling, Small-Wheeled Transport (skates, skateboards, push scooters and hand carts) and Wheelchair travel.


Parking Management: Strategies aimed at making better use of available parking supply. Parking management strategies include preferential parking or price discounts for carpools and/or short-term parkers, and disincentives, prohibitions and price supplements for those contributing more to congestion.


Parking Pricing: This means that motorists pay directly for using parking facilities. Time variable parking pricing can be used as a congestion reduction strategy.


Parking Cash-Out: This means that people (typically commuters, and sometimes residents of multi-family housing) who are offered a free parking space are also offered the cash equivalent when they use alternative transportation modes and so do not impose parking costs. 


Ped-shed (also called a Walkable Area): The area within walking distance of a destination (from “watershed,” the area from which stormwater flows into a stream or lake).


Pedways, which are indoor urban walking networks that connect buildings and transportation terminals.


Price are direct, incremental costs that individual consumers trade off in exchange for using a good or service (perceived, internal, variable costs).


Public Bike Systems (PBSs) are automated bicycle rental systems designed to provide efficient mobility for short, utilitarian urban trips.


Revenue Neutral: Revenue-neutral pricing means that any increase in some consumer charges are offset by reductions in other consumer charges so total revenue collected does not change.


Road Pricing: The general term for any charge for use of a roadway. It is sometimes limited to direct charges, such as tolls, or may include other vehicle fees, including fuel taxes, license fees and parking charges.


Shy Distance: Space left between vehicles or pedestrians as they pass each other. The amount of shy distance required for safety tends to increase with speed.


Smart Growth: Land use development practices that create more resource efficient and Livable communities, with more Accessible land use patterns. An alternative to sprawl.


Sprawl: Dispersed, low-density, single-use, automobile dependent land use patterns (Galster, et al, 2001).


Stakeholder: Individuals or groups that are affected by a decision and have an interest in its outcome.


Time-Variable Pricing: Any user charge that varies by time period as a way to manage demand and reduce congestion. This is the basis of congestion pricing. Such fees are higher during peak periods when the congestion is most severe, and lower during off-peak periods. Many services (telephone, electric utilities, airlines) use time-variable pricing to encourage more efficient use of system capacity and allow users to save by shifting their consumption to off-peak periods. Some road tolls and parking charges are time-variable pricing.


Toll Road: A section of road where motorists are charged a direct user fee (or toll).


Transponder: An electronic tag installed in a vehicle for electronic road pricing. The tag is read electronically by an electronic tolling device that automatically assesses the amount of the user fee.


Transportation Demand Management (TDM): Various strategies that change travel behavior (how, when and where people travel) in order to increase transport system efficiency and achieve specific objectives such as reduced traffic congestion, road and parking cost savings, increased safety, improved mobility for non-drivers, energy conservation and pollution emission reductions. Also called Mobility Management.


Universal Design: Transportation systems designed to accommodate a wide range of users, including people with disabilities and other special needs.


Value Pricing: A synonym for Congestion Pricing that applies when motorists are offered a choice between an unpriced but congested facility, and a Value Priced facility which provides a superior level of service It emphasizes the extra benefits that users receive in exchange for paying a premium.



Wit and Humor

What do you get when you cross a dyslectic, an agnostic, and an insomniac?

Someone who lays awake at night pondering the existence of DOG.



Planning Terms (Stephens 2005)

BANANA: Build Absolutely Nothing Anywhere Near Anything
CAVEmen: Citizens Against Virtually Everything
CEQA: Consultants Employment Quality Act [California Environmental Quality Act]
DBTD/DBTN: Two common vaccines used by planners to “fix” a project they don’t like. DBTD is technically Death By a Thousand Days and DBTN is Death By a Thousand Nicks [also known as the BED Principle—“Bleed ‘em Dry”]
Disneyfication: Architectural fad on a community scale.
Doczilla: Any technical report that should be caged rather than shelved.
DUDE: Developer Under Delusions of Entitlement
Fauxburb: Modern suburb replicating post WWII suburbs with eclectic architecture.
PowerPoint Poisoning: Nauseous state of mind and body induced by viewing “professional” presentations.
Sense of Immunity: Mistaken belief that land use regulation does not apply for a particular neighborhood or site.
SLAPP: Strategic Lawsuit Against Public Participation

Additional Terms

Spinoffs of NIMBY:

BANYs Builders Against NIMBYs [Not In My Backyard Activists]
GOAH Gedoudaheah
GOOMBA Get out of my business area
GUMBY Gaze upon my backyard [Opponents of residential walls and fences]
KIIMBY Keep it in my backyard
NIABY Not in anyone’s backyard
NIMD Not in my district
NIMEY Not in my election year
NIMFOS Not in my field of sight
NIMFYE Not in my front yard either
NIMTOO Not in my term of office
NITL Not in this lifetime
NOPE Not on planet earth
NORF No observable redeeming features
NOT None of that
NOTE Not over there either
NUMBY Not under my backyard
PIITBY Put it in their backyard
QUIMBY Quit urbanizing in my backyard
WIIFM What’s in it for me?
YIMBY Yes in my backyard

Repetitive, monotonous design of buildings and places:

Anyplace syndrome: No ‘sense of place’
B4 and after: Big, bland, beige box…still. Less than inspiring architecture even with extensive landscaping.
Comprehensive Flan: The relatively bland, custard-like filling in many Comprehensive Plans.
Custard development: Bland clustered development.
Déjàvenue: An impression of having seen or experienced the same street before.
Gagplanistan: A place of massively meaningless planning.
Generica: The stores and strip malls you can see in any town in America.
McPlace: Standardized “sense of place.”
Nullibiety: State of being nowhere.
Pablumia: A universal name for urban communities whose ambiances of uniqueness and regional flavor have been eradicated in favor of cookie cutter chain retail stores, restaurants, background music, entertainment and interchangeable local residents all dressed as Americans. The word is from the baby food, Pablum, which has a bland consistency and is completely tasteless.
Placebo: A place that has the appearance, but none of the value of a real place.
Oatmeal Architecture: Contemporary bland, beige, stucco architecture.
Ranchburger: A one-story generic southwestern tract house.
Replaceable places: The same drive-ins, prefab motels, offices, and salesrooms on every road and corner.
Second Street: Average, lackluster or normal. Stemming from the fact that Second Street is the most common name in the United States.
Taupeville: A neighborhood that requires buildings to be all neutral colors, usually beige and taupe. Generic, non-descript, lacking in personality and boring. ‘Over the taupe’ implies something more creative or excessive.
Terrorforming: Extremely bad urban designing. The opposite of “terraform:” to change a planet’s surface and atmosphere so that life as it exists on Earth is possible.
Urban fabric softener: Generic zoning that smoothes out the distinctions between areas.
Vanilla: An adjective for a bland or boring design or plan.


Betty Crocker Suburb: A suburb without child care facilities.
Blurb: Indistinguishable suburban neighborhoods.
Peter Pan Suburb: Suburb designed without consideration for the elderly.
Sitcom Suburb: Neighborhoods of traditional Cape Cod or colonial houses with neat front lawns.
Suburbidity: A thick, hazy condition of sense of place.

…and many other ‘burbs’ such as boomburbs, baddaboomburbs, biz burbs, exurbs, fauxburbs, mallburbs, penturbs, shruburbs, technoburbs, zoomburbs, and vavavoomburbs.


Blandscape architect: Minimalist landscaper.
Bungalow Bill: Tract house architect.
CAVEman: Citizen against virtually everything.
Designosaur: Designer with an enormous impact.
DUDE: Developer under delusions of entitlement.
Hippodamist: A city planner [from Hippodamus, a fifth-century Greek architect, who planned the first city].
Inferior desecrator: Interior designer.
Landscraper: Landscape architect.
Meisterplanner: An artistic or epic planner.

Sense of place:

Scents of place: The odors, smells, aromas, and fragrances associated with a place. The most powerful of the senses is also the most overlooked in planning.
Sense of entry: The front door is big and far away.
Sense of immunity: Mistaken belief that land use regulation does not apply for a particular neighborhood or site.



References And Resources For More Information


Collection of Acronyms Related to Transportation (CART),  (, Transportation Research Group, University of Southampton.



Dr. Paul M. Johnson, A Glossary of Political Economy Terms,  (, Dept. of Political Science, Auburn University.


The Concise Encyclopedia of Economics, (, Library of Economics and Liberty, Edited by David R. Henderson



The Parking Glossary, City of Seattle (


Pedestrian Transport

Pednet, Pednet's International Pedestrian Lexicon (



FHWA, Glossary, and




Active Living by Design 


APA and NACCHO, Jargon Fact Sheet, American Planning Association (APA) / National Association of County and City Health Officials (NACCHO) (


FHWA, Planning Glossary, Federal Highway Administration (


Harvey S. Moskowitz and Carl G. Lindbloom (2004), The Latest Illustrated Book of Development Definitions, Center for Urban Policy Research (


National Safety Council (


Ric Stephens (2005), From NIMBYs To DUDEs: The Wacky World Of Plannerese, Planetizen (


TRB (2009), Glossary of Regional Transportation Systems Management and Operations Terms, Transportation Research Circular E-C133, Transportation Research Board (; at


Transportation Research Thesaurus (, Transportation Research Board, provides a common and consistent language between producers and users of transportation information.



Value Pricing, Glossary of Terms, Value Pricing Homepage, (



ACT (2001), Transportation Demand Management Tool Kit, Association for Commuter Transportation (


ITE, TDM Glossary, Publication Number IR-090, Institute of Transportation Engineers (


TRANSPAC Acronym Glossary (, Contra Costa Commute Alternative Network.


Transportation Planning Glossary, City of Portland (, 2003.



APTA (2001), Glossary of Transit Terminology As Defined by NTD Reporting, American Public Transit Association ($File/Glossary.pdf).


Glossary of Transit Terms (, Sacramento Regional Transit.


Transit Industry Glossary (, Metro Magazine.


Universal Access

FHWA (1999), Designing Sidewalks and Trails for Access: Glossary (

This Encyclopedia is produced by the Victoria Transport Policy Institute to help improve understanding of Transportation Demand Management. It is an ongoing project. Please send us your comments and suggestions for improvement.




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