A French transportation company is using global positioning system technology to track the locations of its busiest buses, which not only helps dispatchers do their jobs better, but also allows the company to transmit estimated arrival times to display screens at bus stops.
The Altair system was developed by the Cityloc consortium of two French companies, Grands Travaux de Marseille departement Herlicq (GTMH) and Societe d’Applications Generales d’Electricite et de Mecanique (SAGEM).
Altair is installed in 100 buses belonging to the Parisian bus company Regie Autonome des Transports Parisiens (RATP), at a cost of about $2,000 per bus.
The system is being used today for buses running along one of the French capital’s busiest routes, from Gare du Nord to Kremlin Bicetre.
Buses are equipped with Altair GPS receivers tuned to the 24 GPS satellites in orbit 10,900 nautical miles above Earth. The GPS constellation is a satellite navigation system deployed by the U.S. Department of Defense and used around the world for geographic location purposes. With a GPS receiver, locations can be determined down to 100 meters or less.
The satellite information received is routed at regular intervals to RATP’s district control office, pinpointing the location of the bus to within 33 feet of its actual location.
The data signal also is transmitted via radio frequency to a battery-operated, liquid crystal display screen at bus stops, informing passengers of the approximate arrival time of the next bus.
“If an emergency is detected on any of the buses, RATP security personnel can intervene immediately,” said the French Technology Press Office, located in Chicago. “Altair also regulates traffic flow, allowing better positioning of buses to avoid two following each other too closely and long delays between buses.”
Drivers have a dashboard display that tells them the location of the bus in front of and behind them.
A back-up system has been created for use when the satellite signal becomes blocked, for instance, when the bus travels through a tunnel or is winding through a very narrow street. Each bus contains a microcalculator that gathers data from the bus odometer and gyrometer. That data is sent to the RATP control office through an internal computer network, so dispatchers can continue to track the position of the bus.
Passengers on the bus can receive announcements concerning time remaining before arriving at the next stop.
Other groups that may be attracted to such a system include police and fire departments, fleets of armored vehicles, ambulance companies and the 14,000 taxis that operate in Paris, the press office said.
