How do I film and edit a car accident? I want a car, moving slowly, to hit a biker, front end.

Multiple angles, quick cuts. If you want it to look good then don't cut away or "cheat the hit". Shot of the car approaching, close of the upper body hitting the hood, falling to the ground, bike flying off. Many ways to come at it.

Ok, thanks for the advice. I understood this is what I should do, but I didn't know if that would be enough. I guess adding food sound effects is the most important. I was thinking of having a shot from inside the car, looking through a shattered windshield, by adding a fake shattered windshield overlay in Final Cut, if that majes sense.

You'll never know till you try...

A fake broken windshield will probably end up hurting the shot more than contributing to it. It is really a job you should attempt in a compositing program such as after effects or shake rather than final cut. Not to say it won't work but I would paln for a backup shot just in case.

Yes multiply images and quick cut. Or maybe film it and speed it up in after effects??

you should've just followed me this morning.