Safety Verification
Approach to Safety Management
Worldwide, there are 144 automated fixed guideway transit systems operating. These carry more than 4.6 million passengers per day (source: Planners Guide to Automated People Movers, 2006/7), operating with 100 times fewer accidents per passenger mile compared to both a) nongrade separated transit such as Commuter Rail and LRT and b) private automobile travel.
Safety in all aspects of the design, construction and operation is ULTra PRT's first priority, and so far as practicable we have designed out risks so as to minimize human error. The wide range of experience held within the team at ULTra PRT, combined with the expertise of members of the independent Safety Verification Team, means that a culture of positive but direct challenge to the detail of the proposal is embedded within the project team.
The Safety Verification Process.
Safety Verification Team
A recent change in the UK Rail Inspectorate safety certification process delegates the main role of safety certification from Rail Inspectorate personnel to a competent, independent safety team. This safety team must be approved by the Rail Inspectorate.
The Safety Verification Team is a group of independent experts whose role is to verify that the design, construction and safety management of ULTra accords with the safety requirements. It has an oversight of every aspect of ULTra. From that system-wide view it identifies and verifies all of those elements that have a direct impact on safety.
Some of those elements are required by the UK’s safety regulations (ROGS) to be verified by a “competent person” before they are put into service. When verifying those elements (new vehicles and infrastructure), SVT adopts a formal process compliant with the duties of a competent person. For Heathrow ULTra, the team is composed of:
- Prof Chris Elliott FREng Barrister, Chairman of the SVT
- Dr John May (Director of the University of Bristol Safety Systems Research Centre)
- Steve Firth (previously UK Rail Inspectorate and Rail Accident Investigation Branch)
- Paul Fairbairn (Director of Mott Macdonald with extensive airport experience, previously with BAA)
Safety Verification for the Heathrow Project
The safety of operating the ULTra system at Heathrow has been assessed using the following approaches, for the reasons stated (see also the Regulatory Approval page):
Hazard Analysis and Risk Assessment
This was started as a creative Hazard Identification exercise, which was subsequently developed into a semi-quantitative evaluation of residual risk once mitigation controls are in place. This exercise served as a guide to the identification of those hazards that required a range of measures to mitigate the risks. It also identified those hazards that were likely to require further numerical quantification and analysis. The Hazards identified were also grouped to form a working list of ‘Primary Hazards’ which has served as a basis for the further QRA.
Quantified Risk Assessment (QRA)
An exercise to analyse and quantify the risks presented by the System, using the primary risks already identified above. The numerical evaluation was conducted to a resolution sufficient to provide confidence in the numerical value of residual safety risk that the System, as designed, presents to passengers, staff and public. This model does not carry the detail of measures that the Hazard Analysis does, but does present a model that is sufficient to give ‘sum total’ system risk values to permit comparison with the agreed numerical safety risk targets for the system. As such, it is this QRA that documents the design assumptions and the hazardous event assumptions and provides the numerical risk data for System acceptance. It is also this numerical model that will be developed and updated through trial running and operations to provide updated safety performance predictions to underpin later stages.
Additional Assessments
- Commentary against Railway Safety Principles and Guidance, Part 1: A valuable additional assessment of the features of the ULTra System against well established criteria for the establishment of safe passenger transport on railway systems in the UK.
- Commentary against Railway Safety Principles and Guidance, Part 2, Section G, Guidance on Tramways: A valuable additional assessment of the features of the Ultra System against well established criteria for the establishment of safe passenger transport on tramway systems in the UK.
- Commentary against APM Standards: A valuable additional assessment of the features of the Ultra System against criteria specified for the design of Automated People Mover (APM) systems in the US. (Ref Standard ASCE 21).
