The invention relates to an overpass which is a three-layer overpass with two bridge surfaces at a crossroad. The overpass is located at a crossroad. The first-layer ground of the overpass is not provided with lanes and only allows pedestrians to pass through. The overpass is provided with two bridge surfaces. And a second-layer bridge floor and a third-layer bridge floor. The overpass is provided with sixteen lanes, and the sixteen lanes comprise four straight lanes, four right turning lanes, four left turning lanes and four U-turn lanes. Figure 1 and Figure 4 are the trend diagrams of sixteen lanes of the flyover. Figure 2 and Figure 5 are directions of lanes passing through the two-layer bridge floor. The second-layer bridge surface of the flyover is rectangular. Figure 3 and Figure 6 are strike diagrams of lanes passing through the three-layer bridge floor and lanes below the three-layer bridge floor. The three-layer bridge surface of the flyover is in the shape of a double-bayonet wrench. The first, second, fifth, sixth, seventh, eighth, thirteenth, fourteenth, fifteenth and sixteenth lanes of the flyover do not pass through the third-layer bridge floor, and the third and fourth lanes are on the third-layer bridge floor in the whole course. 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，为十字路口两个桥面三层立交桥。立交桥位于十字路口。立交桥的一层地面未设置车道，仅供行人通行。立交桥有两个桥面。二层桥面和三层桥面。立交桥拥有十六条车道，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。图1、图4是立交桥十六条车道走向图。图2、图5是经由二层桥面的车道走向图。立交桥的二层桥面形状是长方形。图3、图6是经由三层桥面的车道及三层桥面下面的车道走向图。立交桥的三层桥面形状是双卡口扳手形状。立交桥的1、2、5、6、7、8、13、14、15、16号车道，未经由三层桥面，3、4号车道全程在三层桥面。四条左拐弯车道既经由二层桥面，又经由三层桥面。