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A quadrant roadway intersection adds an additional "quadrant roadway" between two legs of the intersection. This roadway adds two three-way intersections in addition to the original four-way intersection moving all left turns (in right-hand traffic countries) or right turns (in left-hand traffic countries) from the main intersection. The design is intended to improve traffic flow by reducing signal timing phases from four to two in the main intersection. The design is intended for intersections where large artery routes meet in an area of dense development and high pedestrian volume.〔 〕 Proponents also point to a reduction in places where accidents could occur from vehicles potentially crossing paths as well as a low development cost compared to roundabouts or the more complex single-point urban interchange designs.〔〔(【引用サイトリンク】title=Quadrant Roadway Intersection vs. Traditional Intersection )〕 Opponents point to the increase in points where accidents could occur with merging traffic as well as the non-traditional nature of the design which has the potential to confuse drivers. Opponents also refute low cost claims pointing to right-of-way and construction costs of the quadrant road.〔〔 ==Variants== Single quadrant intersections (pictured above) feature a single quadrant road. Double quadrant intersections add an additional quadrant road placed opposite of the other quadrant road. Another variant links grade-separated roads via the quadrant road, typically to bring together a faster road with denser traffic with an overpass (or flyover) over a less traveled, slower road. This design is also referred to as a single-loop intersection.〔 A One Quadrant Interchange uses an overpass and two T-intersections.〔()〕 This is the only and very common one quadrant variant in Germany, where it is called a "Partial At-grade Intersection" ((ドイツ語:Teilplangleicher Verkehrsknoten)).〔Institut für Straßen- und Eisenbahnwesen am KIT: (''Entwurf und Bau von Straßen – Teil: Straßenentwurf.'' ) (PDF; 8,44 MB) Abgerufen am 7. September 2013.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Quadrant roadway intersection」の詳細全文を読む スポンサード リンク
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