A class of functions is introduced which describes how the proportions of people severely injured in two circumstances co-vary as the definition of a severe injury is made more strict or more lax. Two important examples are derived from considering the distributions of injury severity respectively to each be (1) normally distributed with the same variance, or (2) exponentially distributed; the means of the distributions differing. It is shown that severity need only be defined on an ordinal scale for interesting statistical relationships to be obtained. In particular, it was found (using British data) that the variation in injury severity in a number of situations can be described by alterations in the exponent of an exponential distribution of severity, with the boundary between slight and serious injury occurring at one-third the distance from the origin of the boundary between serious and fatal injury. /TRRL/

  • Corporate Authors:

    University College London

    Centre for Transport Studies, Gower Street
    London,   United Kingdom  WC1E 6BT
  • Authors:
    • Hutchinson, T P
  • Publication Date: 1975-4

Media Info

  • Features: Figures; Tables;
  • Pagination: 43 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00133857
  • Record Type: Publication
  • Source Agency: Road Safety Study and Research Fund, Belgium
  • Report/Paper Numbers: Monograph
  • Files: ITRD, TRIS
  • Created Date: Nov 9 1977 12:00AM