intersection

An intersection or an at-grade junction is a junction where two or more roads converge, diverge, meet or cross at the same height, as opposed to an interchange, which uses bridges or tunnels to separate different roads. Major intersections are often delineated by gores and may be classified by road segments, traffic controls and lane design. This article primarily reflects practice in jurisdictions where vehicles are driven on the right. If not otherwise specified, "right" and "left" can be reversed to reflect jurisdictions where vehicles are driven on the left. Types Road segments One way to classify intersections is by the number of road segments (arms) that are involved. A three-way intersection is a junction between three road segments (arms): a T junction when two arms form one road, or a Y junction, the latter also known as a fork if approached from the stem of the Y. A four-way intersection, or crossroads, usually involves a crossing over of two streets or roads. In areas where there are blocks and in some other cases, the crossing streets or roads are perpendicular to each other. However, two roads may cross at a different angle. In a few cases, the junction of two road segments may be offset from each when reaching an intersection, even though both ends may be considered the same street. Six-way intersections usually involve a crossing of three streets at one junction; for example, a crossing of two perpendicular streets and a diagonal street is a rather common type of 6-way intersection. Five, seven or more approaches to a single intersection, such as at Seven Dials, London, are not common.