So much as the queue would take up parts of mainline space.Off-ramp junctions become the bottlenecks of the interchange systems.

• 随着交通量的增大,减速车道不足以提供足够的空间供分流车辆驶离主线,甚至占用主路靠边的部分车道,形成互通立体交叉系统通行能力的“瓶颈”地段。