BACKGROUND: Since its publication in 2010, NCHRP Report 672: Roundabouts: An Informational Guide, Second Edition, has served as a national guide on the different aspects of roundabouts, including planning, analysis, design, and construction.  Also during this period, technology changes have taken place, substantial research on the different aspects of roundabouts has been performed, and many roundabouts have been constructed.  This research and experience gained from these projects has produced many relevant findings and lessons learned.  However, additional research is needed to address the gaps in available roundabout guidance and incorporate the relevant technology, the findings of the new and earlier research, and the lessons learned from the constructed projects into a guide for roundabouts.  This guide will provide updated information and guidance on all aspects of roundabouts and help highway agencies and other organizations address relevant issues when considering the planning and implementation of roundabouts.

OBJECTIVE: The objective of this research is to develop a guide that will serve as the primary source for guidance on all aspects of roundabouts.  The guide will supersede NCHRP Report 672: Roundabouts: An Informational Guide, and other available guidance on roundabouts.

STATUS: Research is complete. The guide is available as NCHRP Research Report 1043, and the work leading to guide developmemt is described in Background and Summary available as NCHRP Web-Only Document 347.