The invention relates to an overpass which is a three-layer overpass with two fork-shaped bridge surfaces at a crossroad. The first-layer ground of the overpass is not provided with lanes and only allows pedestrians to pass through. And the second-layer bridge floor and the third-layer bridge floor are vehicle passing channels. The overpass is provided with sixteen lanes. The sixteen lanes comprise four straight lanes, four right turning lanes, four left turning lanes and four turning lanes. And the second-layer bridge surface is rectangular. And the third-layer bridge surface is a decagonal pattern in the shape of two forks. And the south-to-north lane, the north-to-south lane, the four right turning lanes and the four U-turn lanes are arranged on the second-layer bridge floor in the whole course. And the east-to-west through lane and the west-to-east through lane are arranged on the three-layer bridge floor in the whole course. Six north-south lanes are arranged on the second-layer bridge floor, and the six north-south lanes are sequentially 2, 11, 10, 9, 12 and 1 from west to east. Six lanes in the east-west direction are arranged on the third-layer bridge floor, and from north to south, the lanes 3, 11, 9, 10, 12 and 4 are sequentially arranged on the third-layer bridge floor. And the four left turning lanes pass through the second-layer bridge floor and the third-layer bridge floor.

本发明所述立交桥，为十字路口两个叉形桥面三层立交桥。立交桥的一层地面未设置车道，仅供行人通行。二层桥面和三层桥面为车辆通行通道。立交桥设置十六条车道。十六条车道是：四条直行车道、四条右拐弯车道、四条左拐弯车道、四条调头车道。二层桥面为长方形。三层桥面是两个叉子形状的十边形图案。由南向北车道、由北向南车道、四条右拐弯车道、四条调头车道全程在二层桥面。由东向西直行车道和由西向东直行车道全程在三层桥面。二层桥面上有六条南北向车道，由西向东数依次是：2、11、10、9、12、1号车道。三层桥面上有六条东西向车道，由北向南数依次是：3、11、9、10、12、4号车道。四条左拐弯车道既经由二层桥面又经由三层桥面。