The art of Road Engineering is guided by the standards that are developed for its practice. Standards reflect the research that has been undertaken into the various physical elements of the art. The latest standards applicable to Canadian practice of Road Engineering have been recently reviewed and updated by RTAC (The Roads and Transportation of Canada). So have the policies of AASHTO (The American Association of State Highway and Transportation Officials). Application of standards is not a mechanical process. This paper argues that geometric design is an act of creativity which requires a thorough understanding of safety and cost effectiveness which are of paramount importance to the practising engineer. Provision of adequate sight distance is cited as being the most important standard for which application must be made. The paper discusses the three types of operational sight distance and the three methods of measuring sight distance: stopping sight distance; decision sight distance; passing sight distance; horizonal sight distance; and intersection sight distance. Derivation of each criteria as it relates to the new Canadian and American standards is discussed in conjunction with the most recent research on these matters. Pointers are made to certain inadequacies in the standard dimensions and the Road Designer is encouraged to apply sight distance standards critically. The most recent trends in vehicle dimensions and vehicle performances are also discussed with a view to providing better geometry to cater for their requirements. The paper concludes by bringing sight distance standards and vehicle dimensions together in a discussion on intersection geometry. Creative design must conform to recognized norms so that drivers will respond positively at the approach to at-grade road crossings. (Author)

  • Supplemental Notes:
    • Paper presented during the Proceedings of the Roads and Transportation Association of Canada, Annual Conference, September 1985, Vancouver British Columbia. Volumes 1 and 2.
  • Corporate Authors:

    Transportation Association of Canada (TAC)

    401-1111 Prince of Wales Drive
    Ottawa, Ontario  Canada 
  • Authors:
    • Collings, J C
  • Conference:
  • Publication Date: 1985

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 51-85

Subject/Index Terms

Filing Info

  • Accession Number: 00453617
  • Record Type: Publication
  • Report/Paper Numbers: Volume 2
  • Files: TRIS
  • Created Date: Jul 31 1986 12:00AM