Magic Roundabout (Swindon) Junctions in the United Kingdom"; however, the roundabout provides a better throughput of traffic than other designs and has an excellent safety record, since traffic moves too slowly to do serious damage in the event of a collision. In 2010, the National Cooperative Highway Research Program concluded that the roundabout reduces injurious crashes by three quarters. The roundabout in Drove Bridge has not been the only Magic Roundabout in Swindon; the roundabout at Bruce Street Bridges was until recently a Magic Roundabout. It was converted into a conventional roundabout in 2016, but with many exceptions to highway code priorities, which
Roundabout Devices. Roundabouts are generally not appropriate for placement on motorway or freeway mainlines because the purpose of such facilities is to provide for uninterrupted traffic flow. However, roundabouts are often used for the junction between the slip roads (ramps in North America) and the intersecting road. A single roundabout, grade separated from the mainlines, may be used to create a roundabout interchange. This type of junction is common in the UK and Ireland. Alternatively, separate roundabouts also may be used at the slip road intersections of a diamond interchange to create what often is referred to as a "dumbbell interchange",