NEW APPROACHES TO THE ASSESSMENT OF THE SPATIAL ALIGNMENT OF RURAL ROADS - APPARENT RADII AND VISUAL DISTORTION

A good spatial alignment of rural roads is not only a question of aesthetics. It also concerns the consistent design of safe roads as perceived from a driver's point of view. The problems of curves with distorted appearance by overlaying sag (stretched image) or crest (compressed image) vertical alignment has been known for some ten years. Drivers are unable to retrieve the real geometrical parameters of the engineer's design from the roadband image. The cause is image distortion in curves with horizontal and vertical curvature that has to be limited according to human capabilities of information gathering with the visual system. To quantify the extent of distortion effects the method of calculation of "apparent radii" was developed, that allows the value between the radius in plane and the recognised curvature from the shape of the spatial roadband in the driver perspective to be shown. The use of this method at test and model roadways leads to the conclusion that the calculation of image distortions and apparent radii using simple equations and nomograms is possible and useful.

• Supplemental Notes:
  • The publisher's German name is Forschungsgesellschaft fur Strassen- und Verkehrswesen (FGSV).
• Corporate Authors:

  Road and Transportation Research Association

  Postbox 50 13 62
  D-50973 Cologne,   Germany 
• Authors:
  • Appelt, V
• Conference:
  • 2nd International Symposium on Highway Geometric Design
  • Location: Mainz, Germany
  • Date: 2000-6-14 to 2000-6-17
• Publication Date: 2000-6

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 620-631

Subject/Index Terms

• TRT Terms: Alignment; Calculation; Curvature; Distortion (Optics); Equations; Highway curves; Human factors engineering; Nomographs; Radius; Rural highways; Visual perception
• Uncontrolled Terms: Vertical alignment
• Subject Areas: Design; Highways; Planning and Forecasting; Safety and Human Factors; I21: Planning of Transport Infrastructure;

Filing Info

• Accession Number: 00794819
• Record Type: Publication
• Report/Paper Numbers: FGSV 002/67
• Files: TRIS
• Created Date: Jun 28 2000 12:00AM