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