The Definitive Glossary of Transit Terms

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As with most industries these days, transit is evolving. Technologies are emerging, new mobility options are becoming available, and people are moving more freely than ever before. From bikeshares to buses, to scooters and autonomous vehicles, it can be hard to keep up with the new and exciting developments happening in the world of transportation.

For those of us who work in the industry, however, knowing these terms comes with the work we love and the passion we have to keep our communities moving!

In order to make life a little easier, we’ve created a modern glossary of transit terms. In this glossary, we’ll define everything from transportation policies to new technologies, along with common acronyms and measurements that are used in transportation management every day. Click on a letter below to jump to the word you’re looking for, and let us know if we’re missing anything! We’ll try and keep this list updated as mobility continues to grow. Who knows, we might even invent a new word or two along the way. 

Click on a letter below to navigate to the corresponding section.



The ability and level of ease with which all riders—including those with disabilities, special requirements, or other needs—can access transportation.



Microtransit or other services that are either completely delivered by or through the local transit agency on behalf of their city. The agency has unfettered access to all transit service data while the agency and city are prescriptive on where and how services are delivered. Check out our guide to Agency-Owned Microtransit.


Americans with Disabilities Act (ADA)

The Americans with Disabilities Act is a civil rights law passed in 1990, which guarantees people with disabilities equal access to public transportation. This means that public transportation providers cannot refuse to provide transportation because of a person’s disability. This also requires that a public transit agency’s fixed-route service include a complementary paratransit service for those who may be unable to access fixed-route bus or rail.


Auto Restricted Zone

Areas in which certain types of vehicles are regulated, sometimes by time of day or day of week. Public transit vehicles are usually permitted unrestricted access.


Automatic Fare Collection (AFC)

The collection of components that automate ticketing for a public transit system. AFC systems consist of devices and technology that allow for automating manual fare collection.


Automatic Passenger Counting (APC)

Electronic devices, typically situated near the doors of a bus or vehicle, that count the number of passengers that enter and exit at every stop. APC systems can sync with other operations hubs to provide real-time monitoring and inform route optimizations based on passenger information.


Automatic Vehicle Location (AVL)

Refers to the technology or means for automatically determining and transmitting the real-time geographic location of a vehicle. AVL is typically made possible by GPS.


Base Fare

The minimum cost paid for transit service during base periods, excluding express service charges, transfer charges, or reduced fares.


Base Period

When transit services are scheduled at a normal, constant level. Also known as “off-peak periods”, when base fares are charged.



Roads, or sections of roads, that are dedicated to public buses. Busways may contain tracks or grooves for guiding buses and restricting other traffic.


Car Sharing

A model of car rental where people rent cars for short periods of time, often by the hour. Attractive to people who make only occasional use of a vehicle, as well as those who would like occasional access to a vehicle of a different type than the one they use day-to-day.



An arrangement among commuters or travelers to make a regular trip in a single, shared vehicle. Some high-population areas may offer reserved carpool traffic lanes for vehicles carrying a driver and one or more passengers.


Central Business District (CBD)

The commercial and business centers in cities. CBDs often contain the highest density of commercial space and offices and service as common destination points for public transit.


Complete Streets

An approach to transportation design that requires streets to be planned, designed, and maintained to enable safe and comfortable access for users of all ages and abilities regardless of their mode of transportation. Complete streets allow for safe travel by those walking, cycling, driving automobiles, and riding public transportation.


Computer Aided Dispatch (CAD)

A method of dispatching transit, emergency, or delivery vehicles with the assistance of a computer. Also referred to as a joint system in conjunction with automatic vehicle location (AVL) as CAD/AVL.


Congestion Mitigation and Air Quality (CMAQ)

A federal program that provides funding for transportation projects that reduce emissions and contributes to the reduction of pollutants. Examples of eligible projects include vehicle replacement, facility development, non-recreational trails, and bike-share programs.


Contraflow Lane

Reserved traffic lanes for buses where the direction of bus traffic is opposite to the flow of traffic on other lanes on the same street.



A broad area of land that follows a general directional flow, containing a number of streets, highways, and transit routes, and that connects major sources of trips.



A unique bus or rail service which does not enter the central business district (CBD).


Curb Management

Also referred to as curbside management, curb management is the collection of operations, guidelines, and practices that enable the effective management of curbs and other high-demand areas for applications such as accessibility, transportation, and safety.



Curb-to-curb service is a type of transit service where, at both the beginning and end of the trip, the driver will assist the rider between the vehicle and a sidewalk or other location no more than 15 feet from the vehicle.



When a transit vehicle is operating without passengers on board, often to and from a garage or from one route to another.


Demand-Response Transit

Demand response, or demand-responsive transit, is a broad category of public transit in which shuttles or other shared vehicles will alter their routes during each journey based on rider locations and drop-offs. Demand-responsive transit may include shuttle services to connect riders to employment and transit centers, paratransit, and private sector transit solutions such as Uber and Lyft. Benefits of demand responsive transit services include greater flexibility in routing and scheduling compared to traditional, fixed-route services.


Deviated Fixed Route 

Service routes that are characterized by deviated times, rather than deviated routes. Service routes allow riders to hail a vehicle and request a dropoff anywhere along the route.



A period when a bus or vehicle is not being operated due to repairs or general maintenance.


Fare Elasticity 

Fare elasticity measures how sensitive passengers are to fare price, and can be used to predict changes in service demand as fare price increases or decreases.


Farebox Recovery Ratio 

The fraction of operating expenses which are met by the fares paid by passengers. It is computed by dividing the system’s total fare revenue by its total operating expenses.


Farebox Revenue 

The value of cash, pass receipts, and tokens given by passengers as payment for transit service.


First Mile/Last Mile (FM/LM) 

The beginning or end of an individual trip made primarily by public transportation. In many cases, people will walk to transit if it is close enough. However, on either end of a public transit trip, the origin or destination may be difficult or impossible to access by a short walk. This gap from public transit to destination is termed a last mile connection.


Fixed Route 

Transit services that are provided on a repetitive, fixed schedule along a specified route. Unlike demand responsive transit, fixed-route vehicles only stop to pick up and drop off passengers at specific locations or stops. In order to maximize efficiency, each route in a fixed-route service is usually designed to provide coverage in areas of high ridership.


Fringe Parking 

Parking areas, usually located outside of the central business district (CBD), and most often used by residents of suburban areas who commute downtown.



The time interval between vehicles moving in the same direction or along a particular fixed route.


Intelligent Transport System (ITS)

A broad range of wireless and wireline communications-based information and electronic technologies. When integrated into the transportation system’s infrastructure and into vehicles themselves, these technologies relieve congestion, improve safety, and enhance productivity. ITS is made up of 16 types of technology-based systems, divided into intelligent infrastructure systems and intelligent vehicle systems.



Intermodal, or multimodal, services include more than one mode of transportation and often require connections, choices, and coordination between various modes.


Intermodal Passenger Transport 

See Multimodal Transportation.



A small bus or other vehicle that carries passengers for a low fare. In the early 1900s, jitney was slang for nickel due to the popularity of services that charged five-cent fares.


Layover Time 

Time that is built into a transit schedule between the end of a route and departure for the return trip. Layover time is typically used to recover any delays accumulated during the initial trip and to prepare for the return trip.


Load Factor 

A ratio calculated by the number of passengers carried divided by the total passenger capacity of a transit vehicle.


Mean Distance Between Failures (MDBF) 

A measurement of the average distance in miles that a transit vehicle travels before a breakdown or other failure causes the vehicle to be removed from service.



A broad category that encompasses public shuttles (shared vehicles that connect passengers to public transit or employment centers), paratransit, and private sector transit solutions. In its most agile form (flexible routing, scheduling or both), microtransit can be bundled under the category known as flexible demand response transit services. Learn more about TransLoc’s OnDemand Microtransit Software.


Mixed-Mode Commuting 

See Multimodal Transportation.


Mobility Management 

The application of strategies and policies to reduce or redistribute travel demand. Managing demand can be a cost-effective alternative to increasing capacity.


Mobility On-Demand 

An innovative, user-focused approach which leverages emerging mobility services, integrated transit networks and operations, real-time data, connected travelers, and cooperative intelligent transport system (ITS) to allow for a more traveler-centric approach by providing improved mobility options to all travelers and users of the system in an efficient and safe manner.


Mobility Service Provider (MSP) 

An organization that pairs passengers via websites and mobile apps with drivers who provide transportation services. Transportation network companies are examples of the sharing economy and shared mobility. See also: Transportation Network Companies (TNCs)


Mobility-as-a-Service (MaaS) 

A shift away from personally-owned modes of transportation and towards mobility solutions that are consumed as a service. Such services may be accessed through a joint digital channel, such as a mobile app, that enables users to plan, book, and pay for multiple types of mobility services including public transportation, ride-sharing, bikes, and scooters. 


Modal Split 

The number of people who use alternative forms of transportation in lieu of public transit. It is typically used to determine the percentage of people in an area who use private vehicles as an alternative to public transit.



Transportation services that include more than one mode of transportation and often require connections, choices, and coordination between various modes, such as buses, shuttles, and trains.


Multimodal Transportation (also Intermodal Passenger Transport or Mixed-Mode Commuting) 

Involves using two or more modes of transportation in a journey. Mixed-mode commuting is often used to combine the strengths, and offset the weaknesses, of various transportation options. A major goal of modern intermodal passenger transport is to reduce dependence on the automobile as the major mode of ground transportation and increase use of public transport.


Non-Emergency Medical Transport (NEMT) 

A transportation service provided to individuals who are not in an emergency situation, but need more assistance than a taxi service is able to provide. Oftentimes, these services are specially equipped to transport riders in wheelchairs, stretchers, or with other special needs.


On-demand transit 

A method of passenger transportation that allows for vehicles to alter their routes during each journey based on particular transport demand without using a fixed route or timetable. Vehicles typically pick up and drop off passengers in locations according to passengers needs and can include taxis, buses, or other vehicles. See also: Demand-Response Transit


Onboard Communication (OBC) 

Onboard communication systems can consist of audio and/or visual communication devices such as loudspeakers, LED signs, and video monitors that allow for messages to be relayed to passengers in order to communicate route and stop information or other pertinent messages while onboard a bus or vehicle.



The schedule of work for each driver showing all routes they will operate in a day, including arrival and departure times and specific directions.



Transportation services for people with disabilities who are unable to access traditional fixed route transit such as bus or rail. Paratransit is typically operated as a door-to-door service and can be reserved in advance by riders via website, mobile app, or phone.


Passenger Information System (PIS) 

An automated system for supplying users of public transportation with information about the nature and state of a public transit service through visual, voice, or other media.


Passenger Miles 

The total number of miles traveled by passengers on transit vehicles. Passenger miles can be calculated by multiplying the total number of unlinked passenger trips by the average length of the trips.


Peak Period 

Time periods when transit riding is busiest. Typically peak periods are in the morning and afternoon, coinciding with business commutes and standard highway rush hour.


Peak/Base Ratio 

Calculated by taking the number of vehicles operated in passenger service during the peak period divided by the number of vehicles operated during the base period.



Ride-sharing, shuttle, or other transportation services that are owned and operated by private companies, not affiliated with local or regional governments. Privately-owned transportation services are often reliant on smaller, private vehicles and are typically predominant in high-traffic areas only, with no obligation to serve under-represented populations. 


Rapid Transit 

A rail or bus transit service that operates completely separate from all other modes of transportation on an exclusive right-of-way route.


Recovery Time 

A planned time allowance between the arrival time of a just completed trip and the departure time of the next trip in order to allow the route to return to schedule if traffic, loading, or other conditions have made the trip arrive late. Recovery time is considered as reserve running time. Typically, the operator will remain on duty during the recovery period. (Recovery time is distinct from layover, although they are usually combined together.)


Revenue Service 

The time when a vehicle is available to the general public and there is an expectation of carrying passengers. These passengers either directly pay fares, are subsidized by public programs, or provide payment through some contractual arrangement. Vehicles operated in fare free service are considered in revenue service. Revenue service includes layover and recovery time. Revenue service excludes deadhead, vehicle maintenance testing, school bus service, and charter service.


Reverse Commuting 

Travel that occurs opposite from the main flow of traffic during the morning peak period. Reverse commuting typically occurs from a central business district (CBD) to a suburb or non-central location.



Booking rides and paying for a transportation vehicle with a transportation network company (TNC) through an app. The term ridesharing is also used, but this term has been considered inaccurate, so ride-hailing has been considered a more accurate descriptor.



The number of passengers using a particular form of public transportation. Also a common goal and measure for transit adoption.


Rolling Stock 

The vehicles used in a transit system, including buses, rail cars, vans, and shuttles.


Route Miles 

The total number of miles along a fixed-route transit system.


Seamless Mobility 

Reducing what one could call the institutional friction of travel, potentially by enabling a rider to book a whole journey from door-to-door using a single app, or alerting a traveler that transport has been cancelled and informing the traveler to take a different route or even switch to a different mode of transportation.



Virtual simulations are commonly used by transit providers to predict the performance and viability of a particular transit service given a set of circumstances. Simulations are commonly used when implementing demand responsive or microtransit services alongside fixed route or other service models in order to create optimal coverage within multi-modal service areas. Learn about TransLoc’s Microtransit Simulator!



The expansion of human populations away from central urban areas into low-density, monofunctional, and usually car-dependent communities, in a process called suburbanization.


Transit Desert

Areas that lack adequate public transit service given they contain populations that may be deemed transit-dependent.


Transit-Oriented Development (TOD) 

A type of development that links land use and transit facilities to support the transit system and help reduce sprawl, traffic congestion, and air pollution. It includes housing and complementary public uses (jobs, retail, and services) located at a strategic point along a regional transit system, such as a rail hub or major transit stop.


Transportation Management Area (TMA) 

Designated by the United States Secretary of Transportation as urbanized areas with a population of at least 200,000 people. These designations require additional oversight and gain access to planning benefits in an effort to continually improve planning processes in areas with large populations.


Transportation Network Companies (TNCs) 

An organization that pairs passengers through an app with drivers who provide transportation services for a fee. Transportation network companies are examples of the sharing economy and shared mobility. See also: Mobility Service Provider (MSP)


Travel Demand Model 

Used by transportation planners for simulating current travel conditions and for forecasting future travel patterns and conditions. Travel demand models help planners and policymakers analyze the effectiveness and efficiency of alternative transportation investments in terms of mobility, accessibility, and environmental and equity impacts.


Travel Time 

The time travelled between two destinations.


Unlinked Passenger Trips 

The frequency in which passengers board a public transportation vehicle.


Urbanized Area 

The fully developed area of a central city and its suburbs. A rather complicated, but consistent formula measures for contiguous urban development. According to the 2010 census, urban areas (classified as either larger urbanized areas or smaller urban clusters) must encompass at least 2,500 people with 1,500 residing outside institutional group quarters. 


Vehicle Miles Traveled (VMT) 

One vehicle (whether a car carrying one passenger or a bus carrying 30 people) traveling one mile constitutes a vehicle mile. VMT is one measure of the use of state highways and roads, and is typically aggregated by calculating the total annual miles of vehicle travel divided by the total population in a state or in an urbanized area.


Wait Time 

Wait time refers to the time spent by passengers while waiting for a transit vehicle.


Zone Fares 

A system of fares where a transit system’s service area is divided into zones with different specified rates or fares.