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back to Services & Technology list  Traveler Information > En-route Transit Info
An en-route transit information system provides information to transit riders after their trips have started. This information includes arrival and departure times, information on transfers and connections, information on other regional transportation services, and information on related services, such as park and ride availability. This information can be provided on-board a transit vehicle, at a transit stop or transit center, and at other locations, such as a park-and-ride lots, through various media. --A definition of (ERTIS), from a U.S. Department of Transportation Study: Review and Assessment of En-Route Transit Information Systems.
Levels of Information/Levels of Technology required A. Levels of Information: Real time information Real time data is the most technologically challenging of ERTIS projects to provide. Real time information in the context of ERTIS generally uses some kind of AVL (automatic vehicle location) to determine the location of vehicles in the transit system and project their arrival times, delays and other relevant information and convey it to the passenger. There are several technologies that can be used to locate vehicles. The ones in service now generally have some kind of localized emitter of signals (infrared or microwave) and a receiver of signals. The unit on the vehicle interacts with units on the vehicle route to provide the vehicle location based on the route unit in closest proximity to, and this is communicated to some central control system. It varies from system to system as to whether the emitter or receiver is on the vehicle. It also varies as to whether the route-based emitter/receiver or the vehicle unit reports to the control system. The advantages of this system are that they are relatively simple conceptually, and can be done by the transit operator alone, without interacting with other agencies, etc. A disadvantage—resolution is directly related to the number of units installed on the route. In order to get high resolution, large numbers of receiver and/or transmitters must be placed on the route. Another disadvantage is that the system is route specific, and thus not very portable. This could limit flexibility of bus operations. Another technology that is being tested and implemented is called global positioning system (GPS). GPs uses a system of 21 satellites in earth orbit that transmit signals that can be used to determine a location any place on the globe. This service is provided by the US military and is deliberately downgraded to keep accuracy below the maximum achievable. This inaccuracy can be overcome by differential GPs, which uses a unit set at a known location to correct for the error in the system. A system of this type would use the following set of steps to locate a vehicle. First, the onboard GPs receiver would determine a set of coordinates using the GPs satellite signals. This would be transmitted to the control center where the coordinates could be corrected using the error from the GPs receiver at a fixed known location (probably at the control center). The coordinates are then used to determine the location of the vehicle. Average speed could be determined using several consecutive locations of the vehicle. A major advantage of GPs is that it is not route specific, and it is inexpensive. A small (personal) GPs unit can be bought for under $200, and commercial units may not necessarily be more expensive depending on the level of accuracy needed. The drawbacks to GPs are that it requires line of sight to a minimum of 4-5 satellites in order to give accurate locations (i.e. it doesn’t work in tunnels or under heavy tree cover). Also, the transit operator has to interface with another set of electronic protocols, and is left with some small concerns over the continued production of the GPs service. B. Static Information Static information is information that is not verified against actual conditions. It is the idealized schedule, or to use vernacular, “what should be happening” rather than “what is happening”. A good example is a printed timetable of train arrival times. This is inexpensive, and can be quite effective. This same static information can also be distributed through electronic media, such as display screens, telephone lines, and web sites. The major question about static information is whether or not the technology used to apply it is particularly cost effective. Does displaying information on a CRT display make it any more useful than a printed timetable? An obvious area where such information can be useful is interactive databases. These usually allow a passenger to enter a origin and destination, and then give relevant information to allow trip planning. However, there are some that would contend that this information is not particularly useful in terms of ERTIS, since most travelers will need this information prior to departure on their trip. Static ERTIS can be useful, but the use of advanced technology for such systems should be carefully examined to determine if it is warranted. In general, static information is relatively easy technologically, since the information can be input into some kind of database and queried. Since the information is not time sensitive, static systems can be independent of a central control center. C. Content of ERTIS The content of ERTIS is quite varied, from simple schedule information, to real-time delay reports, to advertising. It is important to choose only information that is relevant to the riders, or of commercial significance. The content is also media-specific. Information relevant to users of interactive kiosks is different than information that is displayed at bus stops or rail stations, which is different from in vehicle information. A list of stations on a line is quite relevant to a passenger on a vehicle, as is the next stop on the line, while a list of train departure times for the same line is most likely not. By the same token, a person at the train station has no reason to know what the next stop of a specific train is, as long as they know when the train arrives at their station. The content of ERTIS is very dependent on what is relevant to a specific community. For instance, Montreal has real-time data available for its rapid transit rail system. However, they choose not to display this data in stations because it runs on 6 minute headways during peak hours and 10 minute headways otherwise, and the information is not going to change people’s behavior patterns. However, on a bus system where headways are 30 minutes or more, knowing from real time data the next arrival time can significantly impact rider behavior. A. Interactive This is a technology that uses some kind of computer link to disseminate personalized travel information. The general format is that of a computer terminal located in a kiosk, which the user queries regarding routes, schedules, etc. A typical session would consist of inputting an origin and a destination, and receiving in return instructions on how to get from one to the other in the most timely or economical fashion. These kiosks can be single or multi-modal, and often include information on local points of interest, etc. In some instances kiosks also have also had real time information on system delays. Another interactive ERTIS situation occurs when cell phones are used to call information hotlines en-route. The effectiveness of interactive, en-route communication has been questioned by some studies, since most of the information that is given by interactive systems is most useful during planning stages of a trip. Also, interactive kiosks are not useful to persons using the transit system on a regular basis, since they already know how to get from origin to destination. This is in part good, since kiosks can only help one user at a time. One major group of users of kiosks is tourists, since they are using an unfamiliar transit system, often to multiple destinations and origins. B. Non-Interactive Non-Interactive Communication generally takes two forms, either some kind of visual display, or an auditory announcement system. Visual displays are easier to automate (its hard to make a voice system that doesn’t sound stilted), and there are a variety of technologies that can be used. One of the more popular is the LED (light emitting diode) display. LED’s are not very high resolution, but they convey text well and are inexpensive. They can also be made on many different scales. Another very well developed technology is the CRT (cathode ray tube), or television type display. These displays are quite flexible in terms of what can be displayed, but they are relatively bulky and the price to get a bigger display area is quite high. Mechanical signboards are also an option, particularly for any area where a large display is needed, such as signs that need to be visible from a highway (to indicate park and ride availability for example). There are many other technologies, such as liquid crystal displays, or route specific schemes. However most are either much more expensive, or much less flexible. Auditory information comes in one or two forms. First, there is the human announcer, which has advantages of great flexibility, and often of greater fluency. The disadvantages are labor costs, and a wider range of quality in announcements made. Automated systems are not nearly as flexible, and are often not as fluent. Also, with any auditory system that broadcasts, the passengers cannot chose to ignore the information. Thus, auditory systems run the risk of becoming a nuisance if overused. Much ERTIS information is disseminated in transit stops or stations. The information can be static or real-time, interactive or non-interactive, and displayed visually or audibly. Examples are announcements concerning destinations of trains at a platform in a rail station, or perhaps a real-time projection of the next bus arrival at a stop, or even a kiosk giving interactive information at a modal transfer point. In vehicle information
is the ultimate en-route information system, but it is technologically
complex to implement, and simpler systems may meet travelers needs
more effectively. An announcement of the next station/stop
is generally most of what people want to know, along with any delays
to the system. Some Examples of ERTIS: A. Real Time information 1. London Bus Route 18/COUNTDOWN This a part of the LLAMD (London, Lyon, Amsterdam and Dublin) project. It uses microwave beacons on the roadside, which are identified by a receiver on the bus. This provides bus location, which is then transmitted from the bus to a central computer. The information is used to estimate the arrival times of at least the next two buses for each stop on the route (the system has been updated to handle up to nine buses on different routes now). The information is displayed at the stops along the route. Extensive surveys and
studies were done to assess the COUNTDOWN project. Here is
a very brief summary of the results.
2. Travlink Project/ Minneapolis/St. Paul Travlink is a Minnesota Guidstar operational test. It is the integration of a computer-aided dispatch (CAD) and an AVL system based on GPs, an ATIS and an automatic vehicle identification (AVI) system. It is a test of the ability of information to cause travelers to change travel plans. It involves the installation of GPs, CAD and AVL on 80 buses out of a fleet of 800. The real-time information from these buses is being combined with traffic information to give a complete picture of travel options and their present condition. The information is available through three kiosks in downtown Minneapolis, which also give information for trip planning, schedules and maps, bus fares, park and ride locations, commuter services, special events, elderly and disabled services, bus service changes and customer information. In addition, monitors at two major bus transfer points give real time status of arriving buses. At park and ride locations, the information is shown on electronic signs. In addition, the buses also have AVI using infrared “signposts” that detect buses as they pass. This is being used to provide a comparison with the GPs data. Furthermore, the bus travel information is being relayed to Minnesota Department of Transportation Traffic Management Center, which is using the buses as probe vehicles in the HOV lanes. The results from focus groups regarding the information were mixed at best. Most people saw little direct benefit from the project. People who didn’t use the bus saw the information as useful, but not likely to change their habits. People who used the bus were comfortable with the system whether or not an ERTIS was implemented. In general people were skeptical about the ability of the system to produce results. The part of the project that was best received was the Trip Planner. 3. Bay Area Rapid Transit (BART) The Bay Area Rapid Transit (BART), (San Francisco/Oakland Bay Area), has an ERTIS that displays real time information. The information is collected through a fixed block data transmission system, which consists of trackside identification readers, which are hardwired to station train control processors and a central computer. These allow the destination of an incoming train to be displayed, as well as the length of the train (to aid in boarding, for instance, off-peak trains may have only 3 cars, while peak trains have up to 10). In addition, there is a loudspeaker system on the trains and platforms that is used to give information on delays to the system. BART is in the process of upgrading its existing system with the addition of a radio tracking system to better locate trains, and Transtar, a trip planning service, which can be manually loaded with delays to the system. 4. Montreal Urban Community Transit Corporation (MUCTC) MUCTC has implemented a service called Visual Communication Network (VCN). VCN has both visual and audio components, and is installed in the subway vehicles. It uses radio communications to locate trains, and also to transmit messages from the VCN control center. The system also has onboard storage for non-urgent messages. The system displays and announces the next stop as it is approached. It also displays/announces delays to the system. When the system is not in use for these purposes it can be used for advertising, using the visual portion of the system only. The advertising is being used in part to cover the costs of the system. The system has been effective. The technical installation went smoothly, and passengers were very positive about the system. 88% of passengers said it made there trip pleasanter 72% rated it good or excellent. They considered it innovative and attractive. The advertising did not receive as high an approval rating, most felt that if the system and the advertising were a package they would live with the advertising. The advertising was found to be very effective, probably due to having a captive audience. Other projects:
The major source for this article was Review and Assessment of En-Route Transit Information Systems. Prepared by: For: Distributed in Cooperation
with: In addition, another general source regarding all transit information is Tarry, S. and L Pickup. Public Transport Passenger Information Through New Telematics Technologies: A Review of New Developments. 1990. Oxford University Transportation
Studies Unit. For the London Bus article, a more detailed explanation of the system, but not the results is found in the following source: Balogh, Stephen and Richard
Smith. Real Time Bus Information—The London Transport Route
18 Demonstration. For the MUCTC article, another more detailed source is American Public Transit Association: 1994 Rapid Transit Conference The Visual Communication Network: An integrated communication, information and automatic station stop announcement system for transit vehicles and platforms Presented by: Some of the BART information is from my own experience as a regular user. Author: Glenn Blackwelder. Last update: 12/15/98
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