> When on the road a car goes over a pothole (bump on the road), what do you call it in English?

We call the hole a "pothole", and we call the resulting action of driving over it a "bump"!

Perhaps you are looking for some other way of describing it? Or some adjectives to describe the feeling, or the sound? Maybe these will help:

> My car hit a pothole and I felt the bump.  
  
> I felt a thump as my wheels hit the pothole.  
  
> As I struck the pothole I heard and felt the bump as my car's suspension took the stress.