CD Candela number of bicycle headlights

Hi all,

How many candela (CD) do you need to have, the level, when shining straigh forward, to not blind others?

How high CD candela, is the limit, that it become annoying/blinding for others?

I have received the Fenix BT20 with 750 lumen, and with 7000 CD, can 7000 CD ,160 meter beam distance be annoying/blinding for oncomming traffic?

Remco

The only standard that I'm familiar with is the German bike light standard. I don't know the numbers, but all the lights that meet the standard do shape the beam so that most of the light is concentrated at a distance, with a pretty sharp cutoff above that. A conventional, symmetric beam won't be able to achieve this. To avoid putting quite a bit of light into the eyes of oncoming traffic, the light must be aimed down enough that the center of the beam is fairly close. The makes it difficult to see the road further away, reducing the effectiveness of the light.

Hard to say if the German standard is available to the public. A lot of those standards have to be purchased from the organization that generates them, in order to fund the research and editing needed to keep them up to date.