Institute for Transportation

About the research

A “Toolbox to Evaluate the System Impacts of Roundabouts on a Corridor or Roadway Network” was developed to assist transportation agencies with assessing the impacts of roundabouts on a corridor or system in terms of transportation planning, corridor and network mobility, land use, flow conditions, access management, and other planning considerations (i.e. pedestrians, emissions). The Toolbox will allow agencies to consider the “big picture” rather than assessing the safety and/or operational impacts of isolated roundabouts.

Many portions of the toolbox can be applied to isolated roundabouts as well.

The toolbox covers the following general topics:

• Roundabouts in comprehensive planning
• Impact of roundabouts on corridor mobility
• Impact of roundabouts on system-wide mobility
• Roundabout performance with unbalanced traffic flows
• Roundabouts in access management
• Impact of roundabouts on other planning considerations

The toolbox contains a summary of available information about each topic, case studies, an analysis of operations for a roundabout in two signalized corridors, and lessons learned.