Countdown & iBus

The existing Countdown system, which tracks buses and relays arrival information to bus stops, is being replaced with a GPS-based system called iBus.

The current Countdown system was introduced as early as 1996, using a combination of roadside and on-bus beacons which track the locations of buses. The roadside beacons send the location of buses to a control centre, and this information is used to display arrival times at bus stops ahead.

Unfortunately the maintenance of the beacon-based system is complex and breakdowns can render the system inaccurate whilst taking a while to be fixed.

London Buses and Siemens will be replacing the current system with a GPS-based one called iBus. Along with the new system which will improve accuracy at the bus stop displays, new services will be introduced such as an audio Countdown at stops, "next stop" information on buses, Internet-based realtime information, and phone (audio), SMS and WAP-based information ("Dial-a-Stop").

Further applications include using the information to reduce "bunching" by sending messages to text displays in a bus drivers' cab telling them to slow down or speed up. Drivers could use this information to even out distances between buses by slowing down to deliberately "hit" a red light at a junction, for example.

The current Countdown system which tracks and displays the predicted arrival times of buses at key bus stops will be overhauled by Siemens at a cost of £116m. The new system will be GPS rather than beacon-based, and will encompass better provision of realtime information via the internet and mobile phones.