Users of the Unitrans bus system serving UC Davis and the city of Davis can now receive real-time information on the location of buses and their estimated arrival time at each bus stop.

The information on the student-run bus service is available through the Web and an automated telephone system.

"We have introduced real-time information to make Unitrans easier to use for regular and occasional riders," said Anthony Palmere, assistant general manager of Unitrans.

Unitrans, which carries about 20,000 passengers a day, contracted with NextBus, an Alameda-based company to provide the convenience. A U.S. Federal Transit Administration grant is paying for about 80 percent of the $350,000 contract; a Unitrans fee paid by students makes up the balance.

NextBus has installed similar systems for more than a dozen university bus systems and major transit systems in San Francisco; Washington, D.C.; and Toronto.

Each of the 50 buses in the Unitrans fleet has been outfitted with a global positioning system tracking unit that transmits its location every 10 seconds. In addition, NextBus algorithms use a bus's location, the schedule and historical data to predict its arrival time at each stop.

Stop predictions and real-time location maps are available through http://www.unitrans.com or directly at http://www.nextbus.com.

The real-time information is also available through Unitrans at (530) 752-BUSS or (530) 204-5529. To use the phone system, riders need to know the three-digit number for their stop, displayed next to the Unitrans logo on all bus stop signs and available through the NextBus Web site.

NextBus also offers automated text messages to let riders know when their bus is a selected number of minutes away.

Unitrans dispatchers will use more detailed real-time information to help handle disruptions in the schedule and to identify problems with late or overcrowded buses. The system also provides archived data that Unitrans can use to evaluate existing services and proposed changes.