APPROACH TO THE EVALUATION OF CHANGES IN TRAVEL UNRELIABILITY: A "SAFETY MARGIN" HYPOTHESIS

Even where unreliability has been recognized as a significant component in the generalized cost of trip-making, few attempts have been made to quantify it in the evaluation of transport improvements. This neglect is perhaps explained by the difficulty of observing a suitable "trade-off" situation in which transport users can trade money directly or indirectly for improved reliability of their transport modes. This article investigates the characteristics of a possible trade-off which might be made by commuters-the allowance of extra time for traveling in order to avoid unpredictable lateness at destination. The form of the costs of a response to unreliability of this nature is considered within a more general framework of the allocation of time under uncertainty or risk conditions. Certain other approaches to the evaluation of travel unreliability are reviewed and a brief outline is given to a current research project which attempts to test the applicability of the "safety margin" in London commuters' timing of the trips that they take to work.

  • Availability:
  • Corporate Authors:

    Elsevier

    Radarweg 29
    Amsterdam,   Netherlands  1043 NX
  • Authors:
    • Knight, T
  • Publication Date: 1974-12

Media Info

  • Features: References;
  • Pagination: p. 393-408
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00095251
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Jul 15 1975 12:00AM