GEMS: Outstanding Issues
(Risk Homeostasis Theory)

• What happens if we introduce the
  - decision aids Reason suggests?

"Each road user has a target (or accepted) level of risk which acts as a comparison with actual risk. Where a difference exists, one may move towards the other. Thus, when a safety improvement occurs, the target level of risk motivates behaviour to compensate - e.g., drive faster or with less attention. Risk homeostasis theory (RHT) has not beenconcerned with the cognitive or behavioural pathways by which homeostasis occurs, only with the consequences of adjustments in terms of accident loss."

Acknowledgement: T.W. Hoyes and A.I. Glendon, Risk Homeostasis: Issues for Further research, Safety Science, 16:19-33, (1993).

• Will users accept more safety?
  - or trade safety for performance?

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