I. Introduction
With the rapid progress of autonomous driving technologies, there have been many recent efforts on related research topics, e.g., scene layout estimation [1], [2], [3], [4], [5], [6], [7], 3D object detection [8], [9], [10], [11], [12], [13], vehicle behavior prediction [14], [15], [16], [17], and lane detection [18], [19], [20].