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Proposed vehicle impact speed - severe injury probability relationships for selected crash types
Speed is recognised as a key contributor to crash severity, and to road safety performance in general. Its fundamental role has been recognised by making Safe Speeds one of the four pillars of the Safe System. In this context, impact speeds above which humans are likely to sustain fatal injuries have been accepted as a reference in many Safe System infrastructure policy and planning discussions. To date, there have been no proposed relationships for impact speeds above which humans are likely to sustain fatal or serious (severe) injury, a more relevant Safe System measure._x000D_
A research project on Safe System intersection design required a critical review of published literature on the relationship between impact speed and probability of injury. This has led to a number of questions being raised about the origins, accuracy and appropriateness of the currently accepted impact speed - fatality probability relationships (Wramborg 2005). The literature review identified alternative, more recent and more precise relationships derived from the US crash reconstruction databases (NASS/CDS). _x000D_
The paper proposes for discussion a set of alternative relationships between vehicle impact speed and probability of MAIS3+ (serious and fatal) injury for selected common crash types. The paper presents the methodology and assumptions used in developing these relationships. It identifies further research needs to confirm and refine these relationships. Such relationships may form valuable inputs into future road safety policies in Australia and New Zealand.