In the first part of this book, an extensive historical review is made of the development of design Policies for the horizontal alignment of road curves, and the concepts underlying them. Particular aspects considered are: (a) the assumptions made about vehicle speeds; (b) the criteria for determining "safe speeds" on highway and intersection curves; (c) the superelevation associated with different degrees of curvature; and (d) the criteria for effecting transitions in curvature, superelevation and pavement width. It is suggested that the adoption of the "assumed design speed" concept in the mid-1930s resulted in a neglect of the study of the actual behaviour of drivers on road curves, and distorted the subsequent approach to other questions such as "safe speeds" superelevation/curvature relationships, etc. None of the major design criteria is found to have been adequately substantiated, having been established without reference to appropriate data on driver or vehicle behaviour. Necessary research is outlined. In the second part of this book, the literature on empirical observations of driver-vehicle behaviour on both highway curves and intersection curves is critically reviewed. Evidence of deviations from the idealised behaviour assumed in current design Policies is pointed out, and several previous interpretations of data are criticised. /Authors/

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 92 p.
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00188436
  • Record Type: Publication
  • Source Agency: ARRB Group Ltd.
  • ISBN: 0-86910-312-1
  • Report/Paper Numbers: SR15 Spec Rpt.
  • Files: ATRI
  • Created Date: Mar 14 1979 12:00AM