GUIDELINES FOR THE INCLUSION OF LEFT-TURN LANES AT RURAL HIGHWAY INTERSECTIONS

Provision of left turn lanes is a major problem which lacks an objective approach. Various techniques and procedures in use have been reviewed. Traffic characteristics at typical Iowa intersections have been measured. A rational approach for inclusion of a left turn lane has been developed, based on relating the benefits to the road user to the cost of providing the added turing lane. An analysis of field data gathered under this project indicates that the use of theoretical distribution to describe vehicle headways is not applicable to rural Iowa two lane roads. As an alternate approach the mass of field data gathered were examined using multiple regression techniques to yield equations for predicting stops and delays. The benefit-cost ratio technique is recommended as the criterion for decision making. /Author/

• Supplemental Notes:
  • Sponsored by Iowa State Highway Commission.
• Corporate Authors:

  Iowa State University, Ames

  Engineering Experiment Station
  Ames, IA  United States  50011
• Authors:
  • Ring, S L
  • Carstens, R L
• Publication Date: 1970-9

Media Info

• Features: Figures; References;
• Pagination: 70 p.

Subject/Index Terms

• TRT Terms: Benefit cost analysis; Left turns; Multiple regression analysis; Regulatory signs; Rural highways; Traffic flow
• Old TRIS Terms: Left turn only; Multiple regression
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00081513
• Record Type: Publication
• Source Agency: National Safety Council Safety Research Info Serv
• Report/Paper Numbers: ISU-ERI-AMES-82100 Final Rpt.
• Files: TRIS
• Created Date: Mar 6 1975 12:00AM