  Intelligent Transportation Systems (ITS) are gaining recognition in
developing countries like India. This paper describes the various components of
our prototype implementation of a Real-time Passenger Information System
(RTPIS) for a public transport system like a fleet of buses. Vehicle-mounted
units, bus station units and a server located at the transport company premises
comprise the system. The vehicle unit reports the current position of the
vehicle to a central server periodically via General Packet Radio Service
(GPRS). An Estimated Time of Arrival (ETA) algorithm running on the server
predicts the arrival times of buses at their stops based on real-time
observations of the buses' current Global Positioning System (GPS) coordinates.
This information is displayed and announced to passengers at stops using
station units, which periodically fetch the required ETA from the server via
GPRS. Novel features of our prototype include: (a) a route creator utility
which automatically creates new routes from scratch when a bus is driven along
the new route, and (b) voice tagging of stops and points of interest along any
route. Besides, the prototype provides: (i) web-based applications for
passengers, providing useful information like a snapshot of present bus
locations on the streets, and (ii) web-based analysis tools for the transport
authority, providing information useful for fleet management, like number of
trips undertaken by a specific bus. The prototype has been demonstrated in a
campus environment, with four-wheelers and two-wheelers emulating buses. The
automatic real-time passenger information system has the potential of making
the public transport system an attractive alternative for city-dwellers,
thereby contributing to fewer private vehicles on the road, leading to lower
congestion levels and less pollution.
