DESIGN CRITERIA FOR CURVES ON TWO-LANE RURAL HIGHWAYS

Geometric design inconsistencies on two-lane rural roads are often characterized through strong operating speed reductions between successive design elements and great disparities between the selected design speed and the measured operating speed, as well as deficiencies between side friction demanded and side friction assumed. Critical driving maneuvers, especially on older roads and unexpected sharp curves, are the results of those operational features; consequently, the safety level decreases. Accidents are the measurable evidence of design, construction and signing deficiencies. Eight curved sites with high accident frequencies were selected through an exactly defined procedure. Three different techniques were used to collect traffic operational data on the selected curves and these are described. The obtained analyzed data reveal main safety problems on all curves. It is proved that an appropriate judgement of the sharpness of the curve from an approach tangent is difficult for drivers and additionally complicated by variations in the length of curvature, vertical alignment and the roadside. To improve the safety on critical locations without changes in the horizontal and vertical alignment, a new traffic warning device is proposed that would give the driver more accurate and effective information about the curve ahead. As shown in this paper, design criteria for curves on two-lane rural roads are related to roadside features, which should simplify a driver's decision of the adequate driving and speed behavior according to the curve characteristics.

• Record URL:
  http://onlinepubs.trb.org/onlinepubs/circulars/ec003/toc.pdf
• 
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00978515
• Supplemental Notes:
  • The proceedings have been edited by the Texas Transportation Institute, Texas A&M University System, College Station, Texas. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Steyer, R
• Conference:
  • International Symposium on Highway Geometric Design Practices
  • Location: Boston, Massachusetts
  • Date: 1995-8-30 to 1995-9-1
• Publication Date: 1998-1

Language

• English

Media Info

• Features: Figures; Photos; References;
• Pagination: p. 25:1-8
• Serial:
  • Transportation Research Circular
  • Issue Number: E-C003
  • Publisher: Transportation Research Board
  • ISSN: 0097-8515

Subject/Index Terms

• TRT Terms: Alignment; Curvature; Data collection; Design speed; Geometric design; High risk locations; Highway curves; Length; Operating speed; Roadside; Rural highways; Traffic crashes; Two lane highways; Visual perception; Warning devices
• Uncontrolled Terms: Side friction; Vertical alignment
• Subject Areas: Design; Highways; Planning and Forecasting; Safety and Human Factors; I21: Planning of Transport Infrastructure; I82: Accidents and Transport Infrastructure;

Filing Info

• Accession Number: 00794682
• Record Type: Publication
• Report/Paper Numbers: E-C003
• Files: TRIS, TRB, ATRI
• Created Date: Jun 12 2000 12:00AM