Rural Roundabouts and Their Application in New Zealand

Traffic circles (roundabouts) virtually eliminate the potential for major accidents, which typically happen at right-angle conflict points. However, minor accidents may increase due to the traffic circle's operating characteristics. This paper presents research on the design and operational guidelines required for the safe application of rural roundabouts, documents current national and international practices in this area, and defines a set of criteria and recommendations suitable for New Zealand. The author cautions that the presence of a roundabout in a rural environment may require supplementary measures on the approach, to warn drivers so they can negotiate it safely. The paper offers ten recommendations for rural roundabouts in New Zealand, based on international best practice: design operating circulating speed of 50 km/h; ensure speed consistency between conflicting traffic streams; satisfy sight distance criteria; ensure circulating carriageway width sufficient for the design vehicle; inscribed circle diameter should be approximately 35-40m for single-lane roundabouts and approximately 60m for dual-lane roundabouts; splitter islands should be at least 60m in length; ensure lighting of the roundabout meets current standards; signs and markings should also comply with current standards; speed reduction measures should be applied where necessary; and drivers should be educated as to the presence and use of rural roundabouts.