由行驶运动产生的车辆车轮的地面图像。如果前后轮的轨迹是一致的，则称车辆跟随该轨迹。例如，如果轮胎底盘相同，则带有转向滚轮，多轮或四轮车轴枢轴转向系统的拖车会沿着轨道行驶。

        Ground image of the wheels of a vehicle which is produced by the travelling motion. If the tracks of front and rear wheels are congruent, the vehicle is said to follow the track. For example, trailers with a steering roller, multi-wheel, or four-wheel axle pivot steering system follows the track if the tyre-base is identical.