A review of geometric design and standards for rural roads in developing countries

This report describes the second part of a study to develop appropriate geometric design standards for use in developing countries. It describes the basis on which standards have been recommended by the Transport and Road Research Laboratory. The derivation of appropriate standards are described under the following headings: cross section; sight distance; alignment; and operational considerations (speed, auxiliary lanes, speed reducing devises, junctions and accesses, bridges and underpasses, signing and road marking, maintenance, consistency of standards, and relaxation of design standards). A review of both the research that has been carried out in the field of geometric design, and of standards currently in use is provided, as are summaries of the recommendations made. For an abstract of the first part of this study see IRRD 809579.