Each vehicle is fitted with a Global Positioning System (GPS) receiver, which transmits speed and location data to a central location. There, a computer running proprietary software calculates the projected arrival times for all stops in the system using this data, along with configuration information and historic travel times. These times are then converted to a 'wait time' and made available via the NextBus website and electronic signs at bus stops and tram stops as well as cell phones, and other wireless devices via the Internet.