mattwnz: It would be interesting to know how many crashes were caused by bright oncoming lights. I suspect quite a few, but probably very difficult to prove. I have had to almost stop when being blinded by highbeams, so they do certainly cause problems.
I would love to know as well, specifically "how many accidents are caused by cars with their fog lights on" It is an offence to use your fog lights unless it is foggy but when was the last time you heard of someone getting a ticket for it.
As for flashing front cycle lights, I hit a cyclist once because when I turned my head looked up the road I saw nothing, but he had a flashing light that flashed about every 1.5 seconds so I completely missed the flash.