London Ambulance Service Failure
The London Ambulance fiasco
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The London Ambulance Service (LAS) Computer Aided Despatch (CAD) system failed dramatically on October 26th 1992 shortly after it was introduced:
• • • The system could not cope with the load placed on it by normal use; The response to emergency calls was several hours; Ambulance communications failed and ambulances were lost from the system.
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A series of errors were made in the procurement, design, implementation, and introduction of the system.
©Ian Sommerville 2004
Software Engineering Case Studies
Slide 1
London Ambulance Service
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Managed by South West Thames Regional Health Authority. Largest ambulance service in the world (LAS inquiry report)
• • • • Covers geographical area of over 600 square miles Resident population of 6.8 million people (greater during daytime, especially central London); Carries over 5,000 patients every day; 2,000-2,500 calls received daily, of which 1,3001,600 are emergency calls.
©Ian Sommerville 2004
Software Engineering Case Studies
Slide 2
Computer-aided despatch systems
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Provide one or more of the following:
• • • • Call taking; Resource identification; Resource mobilisation; Ambulance resource management. CAD software & hardware; Gazetteer and mapping software; Communications interface (RIFS). Radio system; Mobile data terminals (MDTs); Automatic vehicle location system (AVLS).
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Consist of:
• • • • • •
©Ian Sommerville 2004
Software Engineering Case Studies
Slide 3
The manual system to be replaced
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Call taking
• Recorded on form; location identified in map book; forms sent to central collection point on conveyor belt; Form collected; passed onto resource allocator depending on region; duplicates identified. Resource allocator decides on which resource to be mobilised; recorded on form and passed to dispatcher; Dispatcher telephones relevant ambulance station, or passes mobilisation instructions to radio operator if
●
The London Ambulance Service (LAS) Computer Aided Despatch (CAD) system failed dramatically on October 26th 1992 shortly after it was introduced:
• • • The system could not cope with the load placed on it by normal use; The response to emergency calls was several hours; Ambulance communications failed and ambulances were lost from the system.
●
A series of errors were made in the procurement, design, implementation, and introduction of the system.
©Ian Sommerville 2004
Software Engineering Case Studies
Slide 1
London Ambulance Service
●
●
Managed by South West Thames Regional Health Authority. Largest ambulance service in the world (LAS inquiry report)
• • • • Covers geographical area of over 600 square miles Resident population of 6.8 million people (greater during daytime, especially central London); Carries over 5,000 patients every day; 2,000-2,500 calls received daily, of which 1,3001,600 are emergency calls.
©Ian Sommerville 2004
Software Engineering Case Studies
Slide 2
Computer-aided despatch systems
●
Provide one or more of the following:
• • • • Call taking; Resource identification; Resource mobilisation; Ambulance resource management. CAD software & hardware; Gazetteer and mapping software; Communications interface (RIFS). Radio system; Mobile data terminals (MDTs); Automatic vehicle location system (AVLS).
●
Consist of:
• • • • • •
©Ian Sommerville 2004
Software Engineering Case Studies
Slide 3
The manual system to be replaced
●
Call taking
• Recorded on form; location identified in map book; forms sent to central collection point on conveyor belt; Form collected; passed onto resource allocator depending on region; duplicates identified. Resource allocator decides on which resource to be mobilised; recorded on form and passed to dispatcher; Dispatcher telephones relevant ambulance station, or passes mobilisation instructions to radio operator if