Originally Posted by
noglider
cyccommute, I agree that lux ratings don't mean anything without specifying distance. I'm going to bet that bike light makers are assuming some sort of standard distance such as ten meters, which means that the ratings might very well have meaning.
For StVZO, there's a detailed standard for measurement. Standard distance is 10 meters, but that's just the start. As with car headlights, there's a required distribution of light and a prohibition of excessive glare above the beam cutoff.
Lux meansurement is specified at TA 23:
http://translate.google.com/translat...ng.htm&act=url
If a light is to be StVZO approved, it has to be tested and receive a ~K approval number.