TRB's National Cooperative Highway Research Program (NCHRP) Report 672: Roundabouts: An Informational Guide - Second Edition explores the planning, design, construction, maintenance, and operation of roundabouts. The report also addresses issues that may be useful in helping to explain the trade-offs associated with roundabouts. This report updates the U.S. Federal Highway Administration's Roundabouts: An Informational Guide, based on experience gained in the United States since that guide was published in 2000.

This guide is intended to provide information on how to identify safety and mobility needs for pedestrians with the roadway right-of-way. Useful for engineers, planners, safety professionals and decision-makers, the guide covers such topics as: the Walking Environment including sidewalks, curb ramps, crosswalks, roadway lighting and pedestrian over and under passes; Roadway Design including bicycle lanes, roadway narrowing, reducing the number of lanes, one-way/two-way streets, right-turn slip lanes and raised medians; Intersections with roundabouts, T-intersections and median barriers; and Traffic calming designs.