Using an LED torch as a helmet light, will I blind oncoming drivers? I'm planning on buying this LED Torch with this helmet mount.

Could I blind oncoming drivers?
I have a helmet mount very similar, and yes its totally possible to dazzle and annoy any other road user, from pedestrians to other cyclists to motorised vehicle drivers.

Benefits to a helmet light


Its high up above the ground and higher than handlebar lights, so other road users can see it over cars.
The beam follows your head, so you can light up the thing you want to see.
Retro-reflectors everywhere!  Since the light source is near your eyeballs, retro-reflectors work really well and from a very long way away.  A sweep across a dark road will illuminate all those car bumpers and street signs and mailboxes and jogger's jackets and sports shoes.   


Disadvantages of and risks due to a helmet light


Drivers might get dazzled.   I've had a bus driver yell at me from his rolling bus because of my head light.  Admittedly he was more annoyed by the flashing, so after some research I decided to leave it on solid.
Retro-reflectors can be dazzlingly bright when lit up at close range, destroying your own night-sight.
Snaggage risk - your torch/flashlight is a fairly respectable-sized hook and can catch on low hanging branches.  I've caught mine on a washing line at low speed and basically "clotheslined" myself with the chinstrap.
Helmet Function may be compromised by the holder.   Michael Schumacher's skiing accident was exacerbated by the gopro camera mount that focused impact forces on one point rather than spreading them over the head like a helmet is supposed to.  If you were crashing, then the mount should snap off.  What if it didn't snap, or if you impacted vertically onto it?
Weight - torch batteries are dense and the added weight can be noticeable.


Comments

I have mine mounted fairly far back on the helmet, so the torch front barely clears the top.  This reduces snag risk.

The mount is held on by a minimum of velcro, and there's a separate hand strap used as a second line to stop it getting lost.

As mentioned, I use it on solid mode now, however the focus is set fairly tight.  At night my normal posture puts the lights on the road surface around 4-5 metres in front of my wheel.  I tend to look up with my eyeballs rather than my neck.

However, if a car presents in a manner that crosses my path and may require them to give way (to yeild) then I will point the beam below the driver's door.  If I'm passing a parked car that has a person moving in the drivers seat I might light up their wing mirror.

I'd rather annoy someone than get doored by their inattention.
While I won't deliberately dazzle anyone or anything, my priority is everyone using the road arrives home safe.



EDIT Here's a pic showing what I do, for clarity.