You may have read in The Press that Dr Glen Koorey advocated for Christchurch City Council to widen roundabouts, and build more large roundabouts, to reduce crashes for drivers and people cycling (The Press, 31 Aug 2016, page A5). Surprised? So was he! Because that is certainly not what he had told the reporter who rang him the day prior. The online version of the article has been duly fixed by removing this rather wrong statement.
The right thing to do with roundabout designs is to slow everybody as much as possible, and making roundabouts wider and bigger achieves the exact opposite. ViaStrada has recently published a review of German roundabout guidance, as German designs achieve much lower speeds than what our local guidance produced by Austroads allows for. Those German layouts, widely in use in continental Europe, are untested in New Zealand, and we would be keen to work with any Australasian road controlling authority to 'road test' those designs. Please contact Axel Wilke if you would like to discuss this further.