Riskope was contacted by a client to develop an ISO 31000 compliant Quantitative Risk Assessment to be used to support the decision among possible personnel transportation alternatives running between a country’s capital city and a remote operation.
Numerous Man-made and natural hazards impinge on the buses path
The operation had run a shuttle bus service for its personnel from and to the capital city for a decade with no major bus accidents when there was a single fatality accident with a company’s vehicle (not a bus). The driver lost direction and went over the side of the slope, ending up approximately 200m below. Then, in short sequence, another fatal accident occurred, this time with a bus.
Repeated traffic accidents, all over a country, have the potential to trigger crises and violent reactions against a specific company.
The operation immediately invested more than 1MUS$ in (national) road improvements encompassing 15km of heavy-duty guard rails, in follow-up to a list of almost 20 actions defined by a preliminary road safety risk assessment.
Mitigation along a highway may include a variety of techniques, the implementation of which should be a risk based decision process.
The operation publicly declared having the goal to reduce to the lowest possible, but sustainable and reasonable level, the chances of fatal accidents during the shuttling of its personnel. To attain that goal the operation requested that three alternatives would be compared in terms of risks, efficacy, efficiency and sustainability.
A) Status Quo, i.e. a bus service on the road “as is” up to date (base-case).
B) Investing (capital expenditure and increased ongoing maintenance) in mitigation of the existing road.
C) Building a private airport and shuttling personnel from the airport to the operation with buses.
For the study of quantitative relative risks of the three alternatives, it was decided to exclude from the analyzes business interruption and concentrate on accidental harm to people. The study also assumed that the impact of climate changes would be comparable for the three alternatives, reducing the need to develop complicated and very disputable scenarios.
The main aim of the risk assessment was to determine the probability of an event causing single or multiple fatalities for each alternative and from there define a preliminary evaluation of relative risks.
The “differential” relative risks between alternatives can then be used as a preliminary discriminant in the selection of the alternative to be implemented, unless other factors come into play and a long-term comparison shows that the risk profile/uncertainties inherent to each alternative could lead to significant differences in the long term cost and sustainability.
In order to cope with discrepancies and lack of data, like in many other cases, Riskope had to derive ranges of probabilities from incomplete data developed in other countries, other environments, in such a way to cover, to the best of Riskope’s knowledge and understanding, what is expected to be a valid range in the considered cases. Riskope had already successfully used such approaches in ERM efforts for with complex multi-modal transportation system including air, road, rail, barges and ocean going vessels to full client’s satisfaction.
International reputable sources were consulted to allow the definition of expected consequences of accidents, which remain, of course, subject to great uncertainties and can only be defined with broad ranges. Given the lack of data and great uncertainties surrounding this study Riskope adopted a prudent approach and considered large ranges of fatality rates per accident unless data were clearly indicating that smaller values were pertinent and possible.
Pertinent readily available data on road accidents were studied and summarized from the site specific data. The values finally used in the study constitute a blending of all these incomplete information and to remain on the safe side, Riskope adopted rather wide ranges, strutted, however, by factual data gathered to date of consequences and probabilities.
Under various assumptions (see table below) the quantitative total risk ( from ORE) was found to be lower for Alternative C (37% to 65% of Alternative A), with Alternative B having a total risk 73% to 98% of the highest risk Alternative A).
% of A
% of A
|Maximum (worst case)
|Average (2007 data based)
|Reduced Scenario (assumed 2010)
|Average without Hgs (purely theoretical)
Aircraft shuttling (Alternative C) would reduce risks to the lowest relative level among the two considered alternatives despite the necessary residual bus shuttling from the airport to the operation.
Total Risk for the three alternatives. Vertical axis is Total Risk (units are casualties per year).
The various colors correspond to the contribution to total risk by various hazards as coded in the legend (sorry, but we have to preserve client’s confidentiality!).
As mentioned in the study’s report, there are scenarios that could make this aircraft alternative less attractive than it seems (for example if pulmonary edema, dental problems, raising to significant levels because of repeated flying from sea level to the operation).
In summary, this ISO 31000 compliant study concluded that quantitative relative risks could be reduced half by building an airport and completing the shuttling service by bus, under the large set of assumptions that had to be made to cover knowledge and informational gaps.