Working with horses, I am well versed in the standard safety measures - what to wear, where to stand, do's and don't when handling and riding.
On Saturday, someone (I forget who, let's blame Elvis :-)) chased Tigger out of the field shelter. Tigger hasn't been drilled in keeping out of my space (that's another story), but nonetheless swerved to avoid me. I commented, half jokingly, that the best safety measure around horses is a good relationship!
Having really thought about this, I'd say this is generally true. A horse who doesn't want to be with you is unsafe wherever you stand and whatever you do. So is a horse who doesn't listen to you.
Apart from this small example, I can recall two incidents in the last 3 years or so where I was nearly hurt by one of my horses. One was Tigger, again being chased by Elvis, backing away at high speed. He started to stand on my foot, but as soon as he felt it, made a serious effort to rebalance himself and managed to not put any weight down on my foot.
The second incident was more surprising - I had a tooth abscess, hadn't slept all night and was standing rather dazed in a very stupid place (just where the haynet is in this picture. Elvis came in from the field at full pelt, round the corner and there I was. For some reason, I ducked. Elvis jumped me and ran himself into the electric fence! That was some serious effort to avoid crashing into me.
I'm not saying that safety measure such as hard hats, gloves, all the usual stuff aren't necessary (please don't notice the pic above where Amanda is conspicuously without hard hat!). Nor that you should do idiotic things like 'hiding' round the corner as a horse gallops up. But I do think that safest horse to be around, by far, is one who genuinely means you no harm!
If, say, your horse threatens to kick you, do take sensible precautions, but the best thing you could do long term to keep yourself safe is remove her desire to kick you!