EFFECT OF VERTICAL ALIGNMENT ON DRIVER PERCEPTION OF HORIZONTAL CURVES

A driver's perception of the road features ahead is an important human factor that can considerably affect traffic safety and design consistency, and should be addressed in road design. An erroneous perception of the road can lead to actions that may compromise traffic safety. Prior studies have shown that combined horizontal and vertical alignments can cause a wrong perception of the horizontal curvature. In this paper, the hypothesis that the perception of the driver of the horizontal curvature is affected by the overlapping vertical alignment is analytically examined. Computer animation was selected as a 3-D presentation method of the road perspective, and was found to produce a realistic view of the road. A sample of drivers was interviewed to determine the radius of a horizontal curve on a level grade that would look equal to a radius of a horizontal curve overlapping with a vertical curve. Statistical analysis showed that the horizontal curvature looked consistently sharper when it overlapped with a crest curve and consistently flatter when it overlaps with a sag curve. Field measurements of operating speed profiles on a selected sample of combined alignments confirmed that, for the selected sample of alignments, driver behavior on horizontal curves depended on the overlapping vertical curve rather than the vertical grade of the approach tangent.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/8674831
• Corporate Authors:

  American Society of Civil Engineers

  1801 Alexander Bell Drive
  Reston, VA  United States  20191-4400
• Authors:
  • Hassan, Y
  • Easa, S M
• Publication Date: 2003-7

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 399-407
• Serial:
  • Journal of Transportation Engineering
  • Volume: 129
  • Issue Number: 4
  • Publisher: American Society of Civil Engineers
  • ISSN: 0733-947X
  • Serial URL: https://ascelibrary.org/journal/jtepbs

Subject/Index Terms

• TRT Terms: Alignment; Automobile driving; Curvature; Highway curves; Highway design; Highway safety; Human factors; Visual perception
• Subject Areas: Highways; Safety and Human Factors; I83: Accidents and the Human Factor;

Filing Info

• Accession Number: 00960554
• Record Type: Publication
• Files: TRIS, ATRI
• Created Date: Jul 8 2003 12:00AM