Even 40lm of red light is so bright, you'll blind people at a distance of 4m (Knog Blinder MOB Mr Chips V or Cateye Rapid X3).Red rear light - how bright should it be?
Should it be on in daylight as well?
I'm seeing taillights up to about 150 lumen advertised.
With all sorts of blinky/varying modes as well...
I've not seen one integrated with braking, & not sure how that would work, but I understand they exist.
We shouldn't concern ourselves with the lumen output of the lamp, rather we should be concerned with intensity (measured in candela).
Lumens are for bragging rights.Lumens are a proxy for overall performance.