First, this paper describes the probable service life characteristics of transit buses in the United States. This description takes the form of an actuarial survivor curve derived from bus purchase data since 1950; age distribution surveys for 1970, 1972 and 1973; and theoretical curves developed at the Iowa State Engineering Experiment Station. The thrust of the paper is the service-retirement model, which estimates the demand for new transit buses as a function of fleet size and service life. Based on the derived survivor curve, this model compares the survivors of buses installed since World War II to a fleet size established by policy. The difference is the number of buses which must be installed in service by the end of each analysis year to satisfy the policy. This installation requirement represents the demand for buses. A new installation record is created by adding one year to the age of each bus and entering the analysis year's installation as age one. Repeated applications of the survivor curve to this "aging" historical file simulates the service-retirement cycle of a fleet of buses. Lastly the paper tests some hypothetical policies to demonstrate the use of the service-retirement model to estimate transit bus demand. Included with these illustrations is a "best estimate" of the U.S. demand through 1990. /Author/

  • Corporate Authors:

    Highway Users Federation for Safety and Mobility

    1776 Massachusetts Avenue, NW
    Washington, DC  United States  20036
  • Authors:
    • Heightchew Jr, R E
  • Publication Date: 1975-6

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 32 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00130666
  • Record Type: Publication
  • Report/Paper Numbers: No. 12 Tech. Memo
  • Files: TRIS
  • Created Date: Apr 7 1982 12:00AM