Even real life exposure to the carnage of an accident still does not stop all of them. I know of one incident where some kids were caught speeding about the same time as a horrific accident involving the same age group. The country cops took them to the accident to show them what speed does, sadly an hour later the same cops caught them speeding again
There will always be some groups that no matter what you do, you will never be able to get them to change the way they think or act and it is those groups that will have to learn the hard way unfortunately.