Originally Posted by
qwaalodge
I think the best option for everybody is just wear bright flourescent yellow or flourescent orange helmet and shirt.
That stuff never fails to get attention of everyone on the road and you are visible from many miles away. Best of all, no lights to worry about.
Another option is just put bright flourescent colored tape on your helmet. Reflectorized bright flourescent tape even better so you remain visible late in the afternoon if you managed to stretch your ride unintentionally and you forgot to bring any lights.
I disagree. When driving, I notice a cyclist using lighting well before I notice one without, regardless of what they're wearing. My attention is drawn to blinking lights before steady lights.
IMO, blinking lights > steady lights > fluorescent/bright clothing > black/grey/dark blue clothing
As far as the OP's question - sorry, I don't have a good feel for visibility in terms of numbers of lumens. Most daytime running lights I've seen cyclists use seem pretty effective to me, so I think you're OK going with any light recommended by a major manufacturer (Lezyne, Cateye, Cygolite, Blackburn, Dinotte, Nightrider, etc.) for daytime visibility. Perhaps brighter is better, I'd base my decision on affordability at that point.