Roundabout Design

In recent years, roundabouts have proven to provide an effective way to manage heavy traffic volumes at key intersections in place of traffic signal control. Throughout the country, thousands of roundabouts have been implemented, with the data showing improvements in both capacity and safety after a roundabout has been placed into operation. Through training and experience, GRA has become expert in roundabout analysis and design.

At right is shown a drawing of one of five roundabouts under design in the very heavily-travelled corridor of GRA's RIDOT project for the Apponaug Bypass in Warwick, RI. (Reference is made to GRA's highway engineering projects on this web site for a complete project description.) After initial consideration and conceptual design of signalized intersections, the RIDOT decided that an evaluation of roundabouts on the project was warranted. GRA conducted the analysis, developed the preliminary designs and participated with the RIDOT and the Federal Highway Administration (FHWA) in a public workshop to present this alternate concept. With local support, RIDOT made the key decision to move forward with roundabouts on that project.

For a viewing of the simulation results for this location, click on the link below.

-- View The Simulation Here --