Online, On Time

Online, On Time

Alex Vezosa, director of Transportation for Fairfax City, stands in front of a NextBus sign, which is the small display above the larger sign.

In addition to the signs at bus stops, the city also reports bus delays over a secure Web site.

Fairfax City, Va., takes the suspense out of waiting
for the bus


The phones at the Fairfax City, Va., Transportation Department are quieter now. Residents no longer deluge agency workers with questions about when the next CUE Bus will arrive at the Vienna subway station.

Instead, residents can find bus information with a click of the mouse, a tap of the wand or by just glancing up. Fairfax City became one of 12 jurisdictions across the country to install the NextBus system from NextBus Information Systems Inc. of Emeryville, Calif. NextBus provides real-time bus arrival information on bus stop display signs, through the Web and on wireless devices.

The system relies on a combination of the Global Positioning System and mathematical modeling software to predict when the next bus will arrive at all stops along a route.

'There is a perceived notion among the public that even though bus systems are reliable, they want to know when the next one will be arriving,' said Todd Hoffman, public affairs director for Fairfax City. 'Knowing when the bus will be arriving lends a certain assuredness to the system and people like that. From a customer service point of view, it is very important.'

Sign of the times

In July, city officials installed display signs at eight stops along the four routes the CUE Bus travels daily. The signs give predictions of when the next two or three busses will arrive. Residents also can get updates via wireless devices and through Fairfax City's home page. The site also provides a real-time map of the bus' location along the route.

'Once we started using the system, we received very few calls from residents wanting to know when the bus will arrive,' said Alex Verzosa, Fairfax City Transportation director. The department used to get about 100 calls a day.

'We can monitor the buses from our office and this helps our overall management of the bus system,' Verzosa said.

The system, which cost the city $160,000, is simple on the outside, but complicated on the inside.

NextBus equipped each of Fairfax City's 12 buses with a vehicle tracking system that has a GPS receiver and a transmitter that uses the Cellular Digital Packet Data protocol. Three GPS satellites send a signal to the bus and the receiver calculates the bus' longitude and latitude. The modem then sends the data via CDPD to the NextBus server farm.

Bus data's route

Proprietary mathematical modeling software residing on Sun Microsystems servers running Linux uses algorithms and historical bus data collected over a one- to three-month period to predict the bus' schedule. The server sends this information out to the Web, to wireless devices through the Wireless Application Protocol and to the display signs via CDPD.

The system adjusts its predictions for accidents or slow traffic by knowing how often information is sent back to the server.

'The software model is sensitive to the bus route, the time of day and day of week when predicting the arrival times,' said Tom Neale, NextBus vice president of engineering. 'We hear from each bus every 90 seconds or 200 meters, whichever comes first.'

Bus System Diagram

NextBus stores all the bus data on Postgress, an open-source database.

Neale said the system is 98.5 percent accurate in predicting bus arrivals.

Fairfax City Transportation Department employees connect to a secure Web site on the NextBus server via their desktop PCs to send messages to residents through the Web to let them know if there is an accident or mechanical problem that may delay a bus.

The secured site also features pages for officials to post management information.

NextBus can install the mobile hardware for the system in about an hour per bus. The system's cost depends on the number of routes, buses and displays requested, Neale said.

Verzosa said the city plans to add two or three more display signs and is testing solar-powered display signs.

'We pride ourselves on being an e-city and this system fits right our desire to use technology to help residents,' Hoffman said. 'Really, it is all about schedule control and giving residents timely and accurate information.'

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