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[IMAGE]Dig.jpg[/IMAGE]A woman at a bus shelter, upon seeing the digital sign that announces her bus' arrival time, walks off to get coffee. Students at a nearby college campus send a text on their cell phones. Those at home or at work receive an alert and decide to head out to the bus stop - or wait for the next bus. Using various methods, these public transit riders are able to know what time their bus is expected to arrive.
Digital signs on buses have eliminated the need for flip or roll signs, and displays with predicted arrival times in shelters and stations have led to increased rider convenience, allowing for better time management and possibly increased ridership.
The more common display technology for these signs are LED displays, which according to Randy Schilling, parking and mass transit market manager of Daktronics, are much brighter and more readable in an outdoor environment than an LCD screen. The Brookings, S.D.-based company manufactures LED screens for shelters, stations, stops and other off-vehicle locations. Schilling adds that maintenance of an LED sign is significantly less than that of an LCD display.
Troy Whitesel, marketing manager for State College, Pa.-based Avail Technologies Inc., agrees that LEDs are better for bright areas, but adds, "LCD technology continues to evolve. As they continue to get brighter and brighter and more durable and longer lasting, I think you will continue to see more of them being placed in those bright environments as well." Avail's Infopoint module for its Omnipoint system designed for transit operations with up to 350 vehicles, provides real-time information for dissemination to the public.
Differences between an indoor bus display and outdoor shelter display usually address the protection it needs in its specific location. According to Jody Huntimer, marketing manager of Daktronics, the company's most popular display for the public transportation industry is the AF-6120, which meets the voluntary National Electrical Manufacturers' Association (NEMA) 4X standards regarding the enclosing cabinet. It "withstands intrusion of particles, brake dust, elements, wind, rain, and protects the internal components of the display," says Huntimer. In more remote areas without the potential hazards of brake dust, it protects against vandalism.
Onboard signs have other considerations. Larry Hagemann, chief technology officer of DRI Corp., headquartered in Dallas, says, "Signage on board a bus has got to endure the potholes as the bus goes up and down, the shock and vibration," something that a permanently affixed sign at a shelter wouldn't have to withstand.
While amber is the color most commonly used and associated with LED signs, other color options are available. In early 2010, Daktronics will release a tri-colored display available in its AF-6120 product line, adding red, green and amber, all in one package, as an option.
Different options can be useful for color-coding routes, especially in cities with tourists, says Hagemann. Printed maps with a different color assigned for each route help clarify route information. "These colors coordinate with the sign product itself, so you don't need to know English to go from the airport to downtown. If you follow the map, and you see that it's blue, just jump on the bus that has the blue route number on it," says Hagemann. DRI's subsidiaries, Twin Vision and Digital Recorders Inc., offer a palette of more than 200 colors for their on-bus and shelter digital signs.
Reducing Wait Time
Digital signs installed at bus shelters and stops can display the next-bus arrival prediction to awaiting passengers. Using AVL technology and special algorithms to gather bus location information and predict arrival times at each stop, the information is then sent to the individual signs to let waiting riders know the arrival time of the next bus.
Alameda, Calif.-based NextBus Inc. provides the technology for predictions of bus arrival times as well as the digital signs that are installed in shelters and bus stops. Larry Rosenshein, director of business development, says what makes NextBus technology useful is that it allows people the ability to better manage their time.
Cell phones with data plans can access the same information, and those who don't have data plans can text in the stop number to receive a prediction reply within three seconds. Calling in is another option - an automated voice will tell riders when the next three buses are expected to arrive, an important feature that can cut down on wait time in below-zero temperatures.
According to Whitesel, Avail Technologies' bus prediction system displays departure times rather than arrival times. "Sometimes drivers will take a 15-minute break at a particular stop, or they will switch drivers, and that's not going to be a 15- or 20-second stop." By displaying departure times, riders will get a more accurate prediction of when they need to be at the bus stop.
To communicate to the signage equipment, cellular modems can be used to update information to each sign a few times a minute. Radio is another option, as is a network connection. Although a network connection is less costly than a cellular connection, significant infrastructure must already be in place, making it more common in areas such as train platforms or bus stations.
An option that NextBus offers its clients are heavy aluminum signs that have the bus stop number and a phone number for riders to call in for arrival time predictions. Rosenshein recommends these signs for agencies that either don't have a large budget or want to spread the bus-prediction advantages to less frequent stops. Aluminum signs are also an option when there is no electricity available to that area.