The "problem", imho, is not only rare and unlikely in respect to sensibly designed bicycle front lights (we're not talking superbright/off-road arms-race torch lights) but pales into insignificance against all the other problems faced by toddlers on the highway in the dark or of anyone else with eyes lower than a front light and close enough & in front enough to be dazzled below the StVZO cut-off. And it can't be solved by the design of the light.Bmblbzzz wrote: ↑10 Aug 2022, 7:03pmYes, it's not particular to StVZO, I meant that it's a problem which StVZO and similar designs do not address.
There's no way any design can avoid all the possibilities (e.g (differing heights, differing distances, changing gradient) of dazzling eyes lower than the light and illuminate the way ahead adequately - you could mount a light with a severe cut-off a foot off the ground but that wouldn't guarantee not dazzling as you go over the brow of a hill; it wouldn't illuminate the way ahead effectively either. You still need adequate light to see the toddler. the wheelchair user or whoever.
StVZO does significantly eliminate the chance of dazzling others for almost all real life & likely instances; for all other instances, I suggest that the cyclist shielding/directing the light away and/or the recipient shielding or averting their eyes are much more practical and useful solutions.
Most non StVZO LED front lights powerful enough to see on moonless unlit roads are extremely likely to dazzle unless turned down to a very low power setting (in which case they're no longer bright) or angled down (in which case you get a massive blinding bright spot by your front wheel, no night-vision and no illumination ahead). Having used such lights, my experience is that there's no sweet spot that gives good illumination and avoids dazzling.