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When Things go Wrong Human Factors, Accidents and Learning
Who investigates?
Police (Prosecution Authority)
─ Why: Uncover crimes or criminal neglect
─ Result: Establish blame and liability
Organizations, Regulators (private or government investigative agencies) ─ Why: Identify safety problems. Give advice for improvement
─ Result: Learning, and change (hopefully)
Example
Oslo-Stryn night express bus buried by avalanche
09:00 13:00 15:00 16:00 18:00 20:00 22:00 00:00 02:20
Road
Administration Hw 15 closed avlanche danger Road is open
Maintenance contractor
Avalanche control blasting
Sporadic checking
Convoy driving
Free driving
NGI Avalanche danger 4, new warning at 16:00h
Reduced danger assessment based on control work and w forecast. Next warning at 09:00h
Avalanche path
A lot of new snow Only small sluff, road not reached
Less precip and wind
Weather deteriorates, strong wind
Heavy snow fall, strong wind
Weather improves
A 500 m wide avalanche hits the road
Norway Bus Express
Is informed that the road is closed, plans for 3 h detour.
Is informed that the road is open, tells driver to drive original route.
Buss tatt av skred, 8 passasjerer omkommer
Bus driver Arrive late i Oslo because of bad weather
Resting time
Is told to drive original route.
Drives from Oslo Choses original route
Drives in avalanche area
STEP
se
qu
ence
an
alys
is
1
Stress
2
Misplaced charges
3
Uncertainty
4
Risk tolerance too high
5
No risk assessment
6
No update
7
Known problem unmitigated
09:00 13:00 15:00 16:00 18:00 20:00 22:00 00:00 02:20
Road
Administration Hw 15 closed because of avlanche danger
Road is open
Maintenance contractor
Avalanche control blasting
Sporadic checking
Convoy driving
Free driving
NGI Avalanche danger 4, new warning at 16:00h
Reduced danger assessment based on control work and w forecast. Next warning at 09:00h
Avalanche path
A lot of new snow Only small sluff, road not reached
Less precip and wind
Weather deteriorates, strong wind
Heavy snow fall, strong wind
Weather improves
A 500 m wide avalanche hits the road
Norway Bus Express
Is informed that the road is closed, plans for 3 h detour.
Is informed that the road is open, tells driver to drive original route.
Buss tatt av skred, 8 passasjerer omkommer
Bus driver Arrive late i Oslo because of bad weather
Resting time
Is told to drive original route.
Drives from Oslo Choses original route
Drives in avalanche area
STEP
se
qu
ence
an
alys
is
Hierarchic influenceanalysis (AcciMap)
AcciMap diagram format (adapted from Svedung and Rasmussen (2002)
System level
Society, policies, culture DOT only responsible for ALARP
Users do not understand the risks
Laws, regulations
Ambiguous risk tolerances
Permanent measures not used because of warning and control
New maintenace contract every 5 years
Regional DOT
Local interpretation of risk tolerance
Risk underestimated
Normal traffic during high danger
Economic pressure
Contractors Limited time for
forecasting
No inluence on risk tolerance and traffic
Pressure form stakeholders
No continous reassessment
Work overload
Local actors and physical
conditions
Road open in high danger situation
No reassessment of danger development
Consequence The road is used by the public
Bus drives into exposed area
Bus in avalanche, several fatalities
Acc
iMap
infl
uen
san
alys
e
New forecasting
contract every year
Hindsight bias
Cook, 1997
Old view
People make mistakes because of:
Stupidity
Carelessness
Complacency
Incompetence
Defective
How to fix it: Make rules
Enforce rules, make people fearful
Punish violators ─ Fire them ─ Suspend them ─ Retrain them ─ Counsel them
If you follow the rules, you cannot have an accident!
Old view works because..
The organization saves face
Just a temporary glitch, no big changes necessary
One bad apple only – easily removed
Cheap and easy!
Why the old view fails
Basic Attribution Error:
Attribute behaviour to the quality of the person
Underestimate the influence of the situation.
Ingnores local rationality:
Actions were perfectly reasonable, given their point of view and focus of attention; their knowledge of the situation
“Underneath every simple, obvious story about error, there is a deeper, more complex story…”
“Take your pick: Blame human error or try to learn from failure…” (Dekker, 2006)
The new view
The new view
Human Error is a symptom of trouble deeper inside a system
To explain failure, do not try to find where people went wrong
Instead, find out how people’s assessments and actions made sense at the time given the circumstances that surrounded them
Rasmussen (1997)
Drift into failure
Drift into failure
Just culture
An atmosphere of trust
People are encouraged (rewarded) for providing safety related information
It is clear where the line is drawn between acceptable and unacceptable behaviour
It is clear who draws this line
The organization is willing to learn and reform
Accident investigation problem
split second operational decisions get evaluated, turned over, examined, picked apart and analyzed for months
by people who were not there when the decision was taken, and whose daily work does not even involve such decisions.
@infoNGI
NORGES GEOTEKNISKE INSTITUTT NGI.NO
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