iBus is an Automatic Vehicle Location (AVL) system used on the London bus network. It was developed to improve passenger information, service reliability, and bus priority at traffic signals across Greater London.
Background and Implementation
The system was introduced following concerns raised in 2005 that London buses "fail deaf people." It was announced on 16 January 2006 and initially trialled on route 149 for eight weeks. After successful tests, radio presenter Emma Hignett was chosen to record all announcements following a user survey. The system was rolled out across all London buses between 2007 and 2009. By April 2009, all 8,000 London buses had been fitted with iBus equipment.
Technical Operation
iBus uses a combination of technologies to locate buses to an accuracy of approximately ten metres, or its distance from the nearest stop by around ten seconds. These include:
- Global Positioning System (GPS)
- Odometers, including speedometer
- Turn-rate sensor
- Rate gyro
GPS satellite data is passed into a Kalman filter, and other data including velocity and temperature is calculated on the bus and transmitted every 30 seconds via GPRS. The Central System uses this data to make a "best guess" of bus position, even in areas with poor GPS reception. The system contains details of all 19,000 bus stops in London and over 30,000 announcements for approximately 700 bus routes.
Passenger Information
iBus provides audio-visual next-stop announcements on board buses, displaying the route number, destination, and approaching stop name on visual displays while playing corresponding audio announcements. Since March 2014, the current time has also been displayed. When a passenger requests a stop, the display shows "Bus Stopping." Additional safety announcements are played when approaching cycle lanes or slip roads.
The system also feeds data to Countdown signs at bus stops, providing real-time arrival predictions at approximately 3,000 locations across London. Data is supplied to Transport for London's open data systems, enabling external websites and mobile applications to provide live bus position and countdown information.
Service Control and Bus Priority
iBus enables bus controllers to track the precise location of every bus on a route and take action to maintain service regularity. CentreComm, the 24/7 Emergency Command and Control Centre, can track every bus in the fleet and share this information with emergency services in the event of an incident.
The system triggers bus priority at over 4,000 traffic lights across London, allowing buses to request green light extensions or early recalls to improve journey time reliability.
Cost
The cost of fitting iBus to buses and garages up to January 2009 was £18.8 million, part of a Transport for London (TfL) £117 million upgrade to the bus fleet communications system. The original 10-year contract (2005–2015) with Siemens (later novated to Trapeze ITS Switzerland GmbH in 2009) was valued at £162.4 million. A seven-year extension to 2022 was approved in 2015 at a cost of up to £98.2 million, and a further extension to 2027 was agreed in 2022 to allow time for the procurement of a replacement system.
Replacement
In March 2024, TfL signed a 10-year, £160 million contract with INIT to replace the current iBus system. The new system, referred to as iBus2, is intended to improve real-time tracking, disruption and diversion information, and integration with other systems. The contract was awarded following a competitive dialogue procedure and covers both on-bus hardware and back-office services.
