"James Wilkinson" wrote in message
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Nothing is as bright as a daytime running light.

If a DRL wasn't bright, it wouldn't be worth having - in order for a DRL to
stand out from the surroundings, it needs to be brighter than normal
sunlight or bright cloudy light reflected off something white - the purpose
of DRLs is to be seen.

Hopefully they are no brighter than sunlight off a mirrored surface (eg
paintwork, chromework, windscreen) and hopefully the intensity reduces as
the level of daylight does.

Yes, DRLs are fairly bright but I don't find them dazzlingly so, mainly
because they are at the front of cars and therefore are only seen by
oncoming traffic for a short time before the car has passed you. And I don't
notice them being more dazzling on a dull day or at dusk than on a bright
sunny day, which makes me think that there's some adjustment for ambient
light level.

What I *do* find dazzling are rear fog lights when there's no fog, or brake
lights when the driver in front of you in a traffic jam sits stationary, a
few feet ahead of you, with his brake lights on instead of using his
handbrake, or park gear if he's got an auto. I find bright, highly saturated
(monochromatic) lights more distracting and inclined to leave after-images
on my retinas than highly unsaturated white lights.

But we're all different.