Recent geometric design research for improved safety and operations.

This report provides information on selected research published during the 1990s regarding geometric design and roadways, with emphasis on research with safety and operations implications. In part, the incentive for this study was for an updating of AASHTO's 'A policy on geometric design of highways and streets', more commonly referred to as the 'Green Book', the last version of which was published in 1990 for English units and in 1994 for metric units. The results of this review are presented in agreement with the primary sections of the 'Green Book', that is, design controls and criteria, elements of design, cross sections, intersections, and interchanges. (A) This report may be accessed by Internet users at http://gulliver.trb.org/publications/nchrp/nchrp_syn_299.pdf