I'd rather have a really good brake light on the bike (which I do) than a helmet-mounted light. One of my concerns would be that a following vehicle may not even understand what they're seeing, especially if I were to swivel my head while braking.
The best thing that I can do to avoid getting rear-ended is to keep a substantial following distance to the vehicle ahead. That way, if they should slow/stop unexpectedly, my own deceleration gives ample time to vehicles behind me.
I haven't looked into it, but I suspect that the number of bikers that get rear-ended is a really small percentage of bike related accidents.
The best thing that I can do to avoid getting rear-ended is to keep a substantial following distance to the vehicle ahead. That way, if they should slow/stop unexpectedly, my own deceleration gives ample time to vehicles behind me.
I haven't looked into it, but I suspect that the number of bikers that get rear-ended is a really small percentage of bike related accidents.