I'm talking about the high power offroad spots that MTB riders use. Are they legal for on-road use?
A street I regularly dirve down at night is on the way back from a popular MTB ride.
At night riders are often returning along this street with their helmet spotlights on. Of course they automatically look at all oncoming cars. I have never thought of this as more than a temporary nuisance, but the other day one happened to shine directly into my eyes and I was temporarily blinded.
I stopped immediately, and waited there until I could see again - seemed like 30 seconds or so. Quite scary.