I had plenty of practice falling off mountain bikes in my youth (right up to the age of around 40 when I finally decided to stop hucking off every drop/gap in sight). I don't know if I've just been incredibly lucky or all those early mtb crashes (especially in my teens) have helped me to mitigate crash "damage" but I've never really hurt myself too badly in all these years. Having said that I can only remember falling twice on a road bike. The first was a sideways slide across the road when turning too sharply on an icy road (suffered a bit of road rash) and the other was when I ran into the back of someone who braked suddenly in a pace-line. Went over the bars but very fortunately landed on grass and walked away (or rode away to be more accurate). FWIW my strategy when going over the bars is to hold on to the bars initially and then as you rotate over the front wheel release and try to tuck and roll over. It does tend to result in the bike getting flung high into the air (and potentially crashing down on top of you if you are unlucky), but I find that preferable to letting go and doing a "Superman" onto your face! YMMV