Safety Consequences of Flexibility in Highway Design

The AASHTO publication, A Policy on Geometric Design of Highways and Streets, a.k.a. the "Green Book," provides detailed guidance and control values for the design of new alignments or of those undergoing major reconstruction. Most of the design controls represent limits (i.e., maximums or minimums); however, in some instances, a range of design values or even a single value is recommended. For most controls, the "Green Book" indicates that a combination of theory, measurement, and practice has shown the recommended control to provide a safe, comfortable, and aesthetically pleasing roadway. When highways pass through rural communities, questions arise as to the appropriate values for geometric design elements. Research is needed to provide information on the safety consequences (positive and negative) of varying geometric design values in rural communities (The term "rural communities" as used in this project refers to developed areas, which may or may not be incorporated, as well as to the transition zones between high-speed operations in undeveloped surroundings and the lower speed operations in the developed area). Emphasis should be given to the major geometric elements. Flexibility in design is one of the tools designers can use to achieve context-sensitive design. Information from this study will be useful to designers involved with resurfacing, restoration, rehabilitation, and reconstruction projects where flexibility in design is often employed. The objective of this project is to develop guidance to enable project planners and designers to estimate the safety consequences of varying geometric design values for highways through rural communities. The revised final report has been submitted by the contractor. The report will not be published.


  • English


  • Status: Completed
  • Funding: $499407
  • Contract Numbers:

    Project 15-22

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Niessner, Charles

  • Performing Organizations:

    University of Kentucky, Lexington

    Kentucky Transportation Center
    College of Engineering, 176 Raymond Building
    Lexington, KY  United States  40506-0281
  • Principal Investigators:

    Stamatiadis, Nikiforos

  • Start Date: 20010911
  • Expected Completion Date: 20041230
  • Actual Completion Date: 20041230
  • Source Data: RiP Project 5713

Subject/Index Terms

Filing Info

  • Accession Number: 01459503
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 15-22
  • Files: RiP, USDOT
  • Created Date: Jan 3 2013 1:05PM