I'm not sure why this started, but you can tell these videos crashes are edited. They are not real. I think this started out as a way to have fun editing videos and people actually thought it was real and the videos went viral. This entices more people to create videos like this.
When you look at some of them online it is amazing and you almost think that the people are wreaking their cars and there is nothing there. But if you take a look at the video closely, you'll see the drivers of the car, the look on their faces and most of them have their brakes lights on. You know for sure this is a real accident and a person has edited the crash.
A good job in editing, but there is no such thing as ghost cars or ghost crashes.