STOPPING SIGHT DISTANCE CONSIDERATIONS AT CREST VERTICAL CURVES ON RURAL TWO-LANE HIGHWAYS IN TEXAS. FINAL REPORT

Rehabilitating or upgrading existing two-lane roadways sometimes involves design decisions concerning improved vertical alignment and roadway cross section. These decisions are especially critical whenever the existing alignment does not meet current standards. In order to make these decisions in a cost-effective manner, the safety and operational effects of alternative crest vertical curve designs must be known. This study attempted to quantify those effects. In summary, the study concluded that the relationship between available sight distance on crest vertical curves and accidents is difficult to quantify; that the AASHTO stopping sight distance model is not a good indicator of accidents on two-lane roads; and that when there are intersections within the limited sight distance portions of crest vertical curves, there is a marked increase in accident rates. There was also no definitive relationship between available sight distance and operating speed on crest vertical curves.

• Supplemental Notes:
  • Study title: Geometric Design Consideration for Rural Roads.
• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, 1600 E Lamar Boulevard
  Arlington, TX  United States  76011

  Texas State Department of Highways & Public Transportation

  Transportation Planning Division, P.O. Box 5051
  Austin, TX  United States  78763
• Authors:
  • Fambro, D B
  • Urbanik II, Thomas
  • Hinshaw, W M
  • Hanks Jr, J W
  • Ross, M S
  • Tan, C H
  • Pretorius, C J
• Publication Date: 1989-3

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 129 p.

Subject/Index Terms

• TRT Terms: Crash rates; Curves (Geometry); Geometric design; Highway design; Highway safety; Intersections; Operating speed; Rural highways; Stopping sight distance; Two lane highways
• Uncontrolled Terms: Vertical curvature
• Old TRIS Terms: Crest
• Subject Areas: Design; Highways; Planning and Forecasting; I21: Planning of Transport Infrastructure;

Filing Info

• Accession Number: 00494539
• Record Type: Publication
• Report/Paper Numbers: TX-90/1125-1F, Res Rept 1125-1F, TTI: 2-8-87-1125-1F
• Contract Numbers: Study 2-8-87-1125
• Files: TRIS, STATEDOT
• Created Date: May 31 1990 12:00AM