On March 24th, 2016 the Illinois Section of ITE hosted a Lunch and Learn for the TRB webinar: Scalability of Roundabouts with speaker Brian Walsh of WSDOT. The presentation covered the safety and delay benefits provided by roundabouts over a typical signalized intersection. Following this, there was discussion of the flexibility of the modern day roundabout. There are four main roundabout variations: mini roundabout, compact roundabout, conventional roundabout, and central island mountable. For example, a central island mountable roundabout was implemented where there was constrained right-of-way but a need to circulate large trucks. The small mountable roundabout (82') was implemented for under $100,000. Brian also noted that curb details are an important design parameter that must not be overlooked. In order to accommodate truck movements a 2" curb should be use and a rolled curb may be used on the central island. The overall message relayed was that roundabouts can be a very desirable intersection alternative if implemented properly.
The Technical Group looks forward to doing more viewings this year. We want to thank all the attendees for participating in the event and AECOM who was generous to offer their conference room.