To bump means to hit the object without getting killed. To do this, find some short barriers, and delay your jump so that you just stumble over it. You can also do this with tall barriers, but this requires you being on top of a train or wearing Super Sneakers. Another way to do this is to find some lone barriers with nothing next to them. You can then bump into the sides of the barriers. Hope this helps. 我也本来不会google了一下。简单来讲就是撞护栏,但是不能撞死。最容易的方法是你在护栏旁边的道上,经过护栏的时候往护栏的方向靠一下。会减慢速度但是不会撞死。