• Introduction
• Automatic Vehicle Location
  • AVL Technologies
    
• Electronic Fare Payment
  • Electronic Fare Payment Technologies
    
  • Integrated Fare Payment Systems
    
• Traveler Information
  • Types of Traveler Information
• Transit Security
• Traffic Signal Priority
• Precision Docking at Bus Stops
• Computer-aided Dispatch
• "Smart Buses" Case Studies
  

Introduction

ITS applications to transit include Automatic Vehicle Location, Electronic Fare Payment, Traveler Information, Transit Security, Traffic Signal Priority, Precision Docking, and Computer-Aided Dispatch. In-depth reports on most of these technologies are available on ITS Decision (see links to these reports in each section below).

Automatic Vehicle Location

Automatic vehicle location (AVL) is a computer-based vehicle tracking system. For transit, the actual real-time position of each vehicle is determined and relayed to a control center. Actual position determination and relay techniques vary, depending on the needs of the transit system and the technologies employed. Typically, vehicle position information is stored on the vehicle for a time, which can be as short as a few seconds or as long as several minutes. Position information can be relayed to the control center in raw form or processed onboard the vehicle before its transmission. See our Telecommunications Diagrams of GPS-based AVL and Signpost-based AVL for more information.

Transit agencies often incorporate other advanced features in conjunction with AVL implementation. AVL systems normally include the following components:

• Computer-aided dispatch software
• Mobile data terminals
• Emergency alarms
• Digital communications

AVL Technologies

• Signpost and odometer
• Radio navigation/location
• Dead-reckoning
• Global Positioning System (GPS Satellite Location)

Signpost/odometer Systems
The signpost/odometer system has been the most common until recently. In this system, a receiver is mounted on the bus, while transmitters are placed along the bus’ route. Utility poles and signposts are most commonly used as mounting locations for these transmitters. The bus picks up a low-powered signal from these transmitters as it passes by, and the mileage noted. When the bus reports its location, the distance from the last pole is used to locate the vehicle's position on a route. The system can be run in reverse, with the transmitter on the bus and multiple receivers mounted along the route. However, should the bus need to leave the route, there will be no information about the bus, so most agencies prefer to have a receiver on the bus. This older technology has some drawbacks. Creation of new routes requires the placement of new transmitters, and the system is maintenance intensive due to the relatively high number of transmitters and receivers involved.

Radio navigation/location
Radio-location systems use a low-frequency signal to cover the system, and the buses are located as they receive the signal. Loran-C (Long Range Aid to Navigation) is the most common type of land based radio location. Despite the simplicity of the system, it is subject to some major drawbacks. Overhead power lines or power substations can cause signal interference, and signal reception is typically very poor in canyons.

Dead-reckoning
Dead reckoning is among the oldest navigation technologies. Dead reckoning sensors can measure distance and direction from a fixed point (under the most basic setup, an odometer and compass could be used to calculate position from a specific stop on a route). Typically, these systems act as a backup to another AVL system. This relatively inexpensive system is self-contained on the bus. This system has a number of drawbacks. Uneven surfaces and hills can compromise the positioning information. Should the vehicle leave a fixed route, its location will no longer be known since there will be no waypoints off the fixed route. Also, accuracy degrades with distance traveled, and regular recalibration is required (tire circumference changes with wear).

Global Positioning System
Due to the shortcomings of the other AVL technologies, GPS became the most popular system for new installations over the last few years. GPS utilizes the signals emitted from a network of 24 satellites, which are picked up by a receiver placed onboard the bus. The satellite system covers almost all of North America, eliminating the need to place transmitters/receivers along any route. The existence of the satellite system means that the main cost for the agencies result from purchase of the GPS receivers and equipment to transmit to dispatch. While the U.S. military, which oversees the satellite system, has limited the accuracy of the system in the past, it is now allowing more accurate readings. The accuracy and reasonable cost of GPS makes it the most appealing, though it too has some problems. Foliage, tall buildings, and tunnels can temporarily block the satellite signal, and at times satellite signals do not reach specific locations. Typically dead reckoning is used in conjunction with GPS to fill in such gaps.

Click here for a detailed report on AVL.

Electronic Fare Payment

Electronic Fare Payment Systems include two main components: the first component is called Advanced Fare Payment Systems and deals with specific fare media and new hardware devices. This includes a variety of fare card types such as stored value fare payment cards and hardware such as Ticket Reading and Imprinting Machines (TRIM) for handling transfers. The second component is called Fare Integration Systems and deals with the creation of multi-modal and multi-provider transportation networks that link together the fare collection of different operators and modes of transit. Such advances, made possible by the development of new media and hardware devices, allow fare media that can be used for more than one transit mode, such as magnetic strip cards usable for subways, buses, and passenger ferries. The two components, fare payment technologies and fare integration systems, together provide travel that is seamless for the rider but operationally and financially sound for the multiple operators.

Electronic Fare Payment Technologies

Magnetic Strip Cards

The magnetic strip card, which uses a magnetic field to communicate, is one of the most mature forms of electronic fare media today. These cards first appeared in the banking industry in the late 1970’s and are widely used in banking, retail, telephone systems, access control, airline ticketing and transit fare collection. Magnetic strip can be printed on cards ranging from heavy paper to a variety of plastics and they can be coated with a plastic layer for extended life. These cards have been particularly successful in rapid transit systems in the form of readable and writeable cards that require read-write units. These read-write units are installed in computerized ticket vending machines and turnstiles at each rapid transit station. The ticket vending machines accept coins and bills in exchange for magnetic strip tickets reflecting the appropriate value. Inserting the ticket into turnstiles at the beginning and end of a trip allows the read-write unit to deduct the fare according to the length of the trip. 

Pros

• increased convenience due to its capability to store value for more than one trip
  
• reduction of cash and coin handling can improve security and lower costs as well as save the passengers time
  
• allows flexibility in creating a fare pricing system that is more precise by determining the fare based on distance or time of day
  
• the automation of accounting processes increases efficiency and accuracy to lower operations costs
  

Cons

• the rate at which passengers pass through the turnstiles is marginally slower than with traditional token methods
  
• there is a risk of counterfeit that can be countered by using read-only cards or by increasing the coercivity
  
• the read-write units are also subject to their share of failure and require a fair amount of maintenance
  

Contact-Type Integrated Circuit Smart Cards 

These cards, sold at fixed denominations, contain read-write memory that is hard-wired so the value can be decreased but not increased to prevent the risk of counterfeit. The stored value decreases with use until the card is exhausted and then discarded. These cards also contain Read Only Memory (ROM) that allows for non-alterable bits of information that can be used for identification purpose such as ID cards. IC cards are used only for simple applications because they can run on hardwired logic routines and do not require a microcomputer chip. 

Pros

• allows for more storage of information and some simple processing
  
• ROM in the contact-type IC smart card can be used for identification purposes as in the regular IC cards
  
• enable greater security and privacy for stored information by creating methods of positive user identification to secure transactions and encryption to protect data
  
• have the ability to accommodate more sophisticated fare pricing systems, elimination of cash and coin handling, and automation of accounting processes

Proximity Cards (RF Proximity Cards) 

Unlike magnetic cards and IC smart cards, proximity cards do not require direct physical contact between the card and a read-write unit. The most common proximity card today is the radio frequency (RF) proximity card. This type of card contains an induction coil that is coupled with the RF magnetic field generated by another induction coil, located in the read-write unit. The RF magnetic field of the unit serves as the power source for the circuits in the card and when modulated, carries signals to the card. The card must also contain some small power conditioning circuitry in order to attain power from the RF magnetic filed and to regulate it into a useable form. Another option is to include a battery in place of a power conditioning system. The card itself also has the capability of sending signals back to the read-write unit using the same coil or a separate coil or antenna.

Pros

• only require that the card and the read-write unit be in close proximity thereby eliminating the need for insertion into a unit for precise positioning of the card (this significantly reduces the time consuming processes of the contact-type method)
  
• lack of physical contact between the card and the reader also serves to lengthen the life of the card by reducing wear and tare
  
• offer potential in inter-modal and inter-operator transfers with advanced security features

Capacitively Coupled Cards 

Capacitively coupled cards are cards that use capacitive coupling in order to perform read-write functions. This type of card contains two or more areas of metal foil, that are covered by extremely thin layers of a plastic insulator. When the plastic coated metal foil layers are closely aligned with the plastic coated metal foils contained within the read-write unit, a capacitor is created that couples the circuits of the two components. This coupling allows the communication and transfer of information between the card and the read-write unit by supplying the required power and signals. The capacitively coupled card is similar to the RF proximity card in that it does not require direct physical contact between the circuits of the card and the circuits of the read-write unit. This card is different from the RF proximity card because it still requires insertion into a read-write unit for precise positioning and does not come along with the benefits of contactless methods. The capacitively coupled card has not yet been used for practical application in the transit systems. 

Click here for a detailed report on Electronic Fare Payment

Integrated Fare Payment System

Fare integration systems are fare payment systems that are intended to simplify travel and make it more efficient among different transit modes and operators. There are three types of integration that are currently emphasized in the Fare Integration System today. One type involves linking the fare payment systems among different modes of transportation that are managed by a single transit operator. A second type links together, different transit operators to the same system of fare payment. A third type of integration links transit fare payment systems with consumer financial systems such as banks and credit unions. The goal of these mergers is to increase convenience for the passenger and operational effectiveness for the operators.

Click here for more information on Fare Integration Systems

Traveler Information

Some bus routes provide real-time bus arrival information at bus stops (frequently referred to as "next bus" signs). These signs use an automatic vehicle location (AVL) system; in this system, a GPS unit onboard the bus communicates its ID# and location information to an information center. Taking into account the actual position of the bus, its intended stop, and the typical traffic patterns of its route, this center estimates arrival information and sends this info to an electronic display at the bus stop. Next bus signs can be found in the San Francisco MUNI system at major stations along the entire J, K, L, M, and N lines and along the 22 Fillmore line. They can also be found in Denver along the Vail transit route and in Rehoboth Beach, Delaware. See our GPS-based AVL Telecommunications Diagram for more information.

Typically, traveler information breaks down into two categories: static information, which is known in advance and changes infrequently, and real-time information, which changes frequently.

Static information includes:

Real-time information is what travelers have repeatedly said they value the most. Real-time information includes:

Types of Traveler Information

Traveler information can be divided into the following types of info (click on the link for more detailed information):

Enroute information - provides drivers information pertaining to traffic conditions, incidents, construction, transit schedules, weather conditions, hazardous road conditions, and recommended safe speeds while en-route. 

Enroute transit information - the information that is available to transit riders after they start their trips (includes arrival and departure times, availability of services such as park and ride, transfers within the system and connections to other modes).

Pretrip information - informs travelers of traffic and transit conditions, so they can assess travel options before selecting a route, mode, departure time, or deciding whether to make a trip.

Route guidance - technology that enables a driver to take the route that most closely matches his requirements.

Telematics - encompasses consumer products, services, and supporting systems that deliver information, communication, and entertainment to vehicles and mobile devices (e.g. personal digital assistants (PDAs), pagers, cellular phones)

Traveler services - tells travelers about attractions and travel conditions along their route.

Click here for a detailed information on Traveler Information

Transit Security

The security of a transit system is part of the service that the transit agency provides. Passengers regard their safety as the agency's responsibility. Crimes committed in transit systems include disorderly conduct, public drunkenness, non-payment of fares, theft, harassment/threat, narcotics, weapons violation, purse snatching, simple assaults and batteries, robberies and attempts, aggravated assaults, sexual assaults, rapes and attempts, and homicides and attempts (Needle, 1997). These crimes occur in transit stations, at transit stops, or on board transit vehicles, and often at night.

Most safety and security improvement measures can be categorized as one of the following types: patrol and security, design actions, media and information campaigns, technological innovation, transit service improvements, and increasing sanctions of offenders (Ingalls 1994, Wallace 1999). New technology, such as monitors and automatic alarms, can improve transit system security. The main technologies used are:

• CCTVs
• Call boxes/emergency phones
• Alarms
• Automated ticketing and fare systems.
• Automatic Vehicle Locations Systems (AVL)
• Pager systems alerting travelers of the next bus arrival

Other strategies to prevent or control crime include: patrol and security, design actions, media and information campaigns, transit service improvements, and increasing sanctions of offenders.

Click here for more information on Transit Security

Traffic Signal Priority

Traffic signal priority is the idea of giving special treatment to transit vehicles at signalized intersections. Since transit vehicles can hold many people, giving priority to transit can potentially increase the person throughput of an intersection. Signal priority is being more widely deployed in North America to address traffic congestion, caused by traffic signals, for on-street transit service.

There are two basic types of bus signal priority:

1. Active priority: Each bus is detected on approach to an intersection and the signals are then changed. Active systems can be a combination of real or fixed-time control strategies, and schedule or headway-based control strategies. Active concepts are more effective and widely used.
   
   
2. Passive priority: Traffic control devices are adjusted to suit the bus schedule along the route in general using a combination of fixed-time and schedule-based control strategies. In some applications, passive priority is implemented only at certain intersections – primarily it favors roads with significant transit usage, often close to the buses origin point where schedules are most likely to be adhered to – while the entire corridor has an active priority system. Passive priority does have the benefit of being lower in cost, however it has limited potential to improve bus operations.

There are many different options for signal priority logic. Real-time, adaptive systems can incorporate information on traffic flow, flow coordination, bus schedule adherence, and prior bus arrival times.

Queue Jumpers: A queue jump lane is a short stretch of bus lane combined with traffic signal priority. This lane enables buses to by-pass waiting queues of traffic and to cut in front by getting an early green signal. A special bus-only signal may be required. The queue jump lane can be a right-turn only lane, permitting straight-through movements for buses only. A queue jump lane can also be installed between right-turn and straight-through lanes. A similar arrangement can be used to permit a bus to cross traffic lanes to make a left turn immediately after serving a curb-side stop.

Precision Docking

Precision docking refers to a variety of systems designed to enable a vehicle to align itself in exactly the same position at a station every time. Precision docking at bus stops uses sensors on buses and on the roadside to indicate the exact place where the bus should stop. Bus doors opening at the same location each time make it possible for passengers to be in position for immediate boarding once a bus has stopped, shortening dwell time. This precision can be used to achieve level, gap-free access by bringing the bus close alongside platforms. It can also allow for direct wheelchair access from a loading platform to the floor of the bus (without taking extra time). Precision docking has the following advantages:

• bus drivers will not need to make multiple attempts to park accurately
• bus drivers will not approach too close to the curb and damage the bus tires, which creates excessive maintenance costs
• cumbersome moveable ramps will not be needed

Computer-Aided Dispatch (CAD)

Computer-Aided Dispatch (CAD) software integrates transit operations by giving transit dispatchers and supervisors decision support tools to manage the operating environment. The primary CAD functions are real-time monitoring of operations and providing decision support to respond to delays and disruptions of service. Decision support recommendations include adjustment of vehicle headways, dispatching replacement or additional vehicles, or reporting incidences. Although few CAD systems have been standardized, many transit operators have noted the cost savings and efficiency gains that CAD affords.

How does CAD work?
Dispatchers are responsible for carrying out a series of actions when responding to a call from a bus operator. They usually have access to a CAD screen and an Automatic Vehicle Location (AVL) screen, which help them identify and respond to problems on their bus routes. When a bus operator calls, the dispatcher sees a message showing the bus number on the CAD screen (which prioritizes the operator calls). The dispatcher selects the vehicle calling from the incident list and refers to their Automatic Vehicle Location screen for its location. The dispatcher can enter an "incident code" that identifies the type of problem the bus is experiencing as well as call the bus operator directly. The CAD/AVL system helps dispatchers track route performance by notifying them of late or off-route buses. Dispatchers can also typically communicate with buses individually or collectively (i.e. an entire route); they can send text messages or talk via radio.

Link to list of existing CAD software used for public safety

Smart Buses Case Studies

Long Beach TranSmart
Long Beach Transit is in the process of implementing TranSmart, a satellite-controlled, computerized system for tracking its bus fleets. Buses are equipped with GPS so that the dispatch stations can track their location, which allows transit supervisors to alert passengers of where the bus is and when it will arrive (to the minute). Passengers receive real-time bus location information on electronic TranSmart signs placed at select stops. Voice announcements will be tied to the GPS system to tell passengers on board and waiting at bus stops where the bus is located and what stop is coming up. Buses will also have LED displays on board to alert passengers of where they are on the route and how much time until their stop. Passengers will eventually be able to figure out where their bus is via cell phones, the Internet, or telephone.

University of Newcastle's "Phone and Go" Service
The University of Newcastle upon Tyne's Transport Operations Research Group (TORG) and Northumberland County Council are evaluating the Phone and Go service. This service is similar to Dial a Ride schemes, except that it is available to everyone. Passengers using this service phone the Travel Dispatch Centre (TDC) in advance of their trip; a dispatcher uses computer software to book the trip and determine the most efficient route. This route information is then sent to the Phone and Go bus using GSM text messaging (similar to wireless technology) and the bus--taking into account the other booking requests--embarks to pick up the passenger. Thus far, mostly pensioners and mothers with young people are using the Phone and Go service, but the project leaders are hoping this service can help alleviate the transit problems of this rural area.

King County Metro and the University of Washington "Mybus" program
King County Metro in Seattle has been running the Mybus program that allows passengers with Internet-ready cell phones or palm pilots to access information that will tell them whether or not their particular bus is on time or not. Metro has another Internet-based program that allows users to view bus locations within a system map on their home computers. Metro also plans to put up bus signs that provide real-time bus arrival times.

Oregon's Tri-Met Program
Tri-Met has deployed several advanced ITS technologies to improve the delivery of service on bus and rail. The computer-aided bus dispatch system (BDS) and the rail central control system (CCS) currently display the location and schedule status of all fixed-route vehicles to dispatchers and rail controllers, respectively. The Tri-Met project would allow for real-time transit information to be displayed to transit customers via communications technologies (i.e. cell phones). This project will also implement automated stop announcements on buses to assist the visually impaired.

Better buses in Raliegh, North Carolina
Buses in the Triangle will be equipped with several types of technologies aimed at improving ridership and customer satisfaction. The cameras will take footage of activities both within and outside of the bus (i.e. accidents). Stop-announcement technology will let passengers know of their location along a given route. Dispatchers can track the buses using GPS and keep traveler schedule information updated.

Houston, TX Metropolitan Transit Authority "Integrated Vehicle Operations Management System (IVOMS)
The Metropolitan Transit Authority approved funds for an Integrated Vehicle Operations Management System (IVOMS). A total of 1,350 vehicles will be equipped with next stop announcement units, mobiles radios for data radio communication and Automatic Passenger Counters. Transit Signal Priority systems will also be installed on 1,072 vehicles and used at roughly 1,250 intersections. Additionally, electronic bus stop signs will be installed and will display next bus arrival times for each route.