Useful Links for Information about Modern roundabouts
Transport Research Laboratory, UK
Ourston Roundabout Engineering
The Washtenaw County Road Commission (Michigan) has recently completed a modern roundabout webpage. It does a great job of covering the varied topics with good detail; the information is well formatted and easy to find.
Washtenaw County Road Commission
Design Resources
Capacity Analysis
Roundabout Capacity Empirical Method - John Pierce, TRL
Rodel Summary - Mark T. Johnson
Unequal Traffic Distribution - Barry Crown
RODEL
Design Guides
Example Plan Sets
Marking Layout of Three Lane Roundabout
Safety Studies
"Can Modern Roundabouts Safely Accommodate All Users?"
Gene Russell, Kansas State
Insurance Institute Paper on Roundabouts
Insurance Institute Roundabout Crash Reductions
Maryland Roundabout Safety Study
Roundabout Accident Analysis for Truckee, CA
Double-Lane Speed Study - FHWA