Decision sight distance (DSD) has been defined as the distance at which drivers can detect a hazard or a signal in a cluttered roadway environment, recognize it or its potential threat, select an appropriate speed and path, and perform the required action safely and efficiently. Research was done to relate this concept to specific road types, design speeds, traffic operating conditions geometric features, and driver attributes. In phase 1, a model of the hazard-avoidance process was formulated to be used as a basis for quantifying DSD, and preliminary DSD values were developed based on the average times for the elements of the model derived from literature sources. In the 2nd phase, 19 subjects drove an instrumented vehicle through eight typical highway situations to validate the preliminary DSD values. The findings of the literature synthesis and the results of the field validation experiments indicate that the decision sight distance is operationally valid. A recommended range of DSD values are presented. Recommended applications are discussed.

Media Info

  • Media Type: Print
  • Features: References; Tables;
  • Pagination: pp 11-13
  • Monograph Title: Aerial surveys, geometrics, surface drainage, ecological impacts and safety appurtenances
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00316650
  • Record Type: Publication
  • ISBN: 0309029910
  • Files: TRIS, TRB
  • Created Date: Oct 27 1980 12:00AM