il padrone wrote:VRE wrote:Chris249 wrote:... extra lumens can prevent the driver seeing the shape of the object (in this case, a rider and bike)
Which can actually be a GOOD thing: if the motorist believes a motorbike, not a bicycle, is approaching, they tend to treat it with more respect. Sad, but true.
+1
That has been my experience, as I have posted about elsewhere.
The problem is that if the driver sees only a single point then they have no way of knowing how far away the object is, or the speed at which it is moving. See, for example, "Automotive Lighting and Human Vision" by Wordenwerber et al.
Therefore if your light is bright enough to effectively destroy the driver's ability to see the rider, you are taking away vital information about your position and speed.
Secondly, motorists have MASSIVE problems interpreting the speed of motorcycles by their headlights, and can easily be out by some 60% or more - see "Judgments of approach speed for motorcycles across different lighting levels and the effect of an improved tri-headlight configuration" by M. Gould a, D.R. Poulter b, S. Helman c, J.P. Wann. So it appears that there's little solace to be found in dazzling drivers into thinking you are a motorbike.
I'm no expert in these things, but I'm married to someone who has a PhD in the accuracy of visual perception of moving points of light, was top honours student out of about 5,000 undergrads at her uni, has a fellowship at Australia's top university, rides each day, and lost her previous husband when his bike was struck by a car in low-light conditions. Although she has not looked at this issue specifically, her gut feeling is that extra power does NOT equal safety. I think I'll take such an expert's point of view on this.
There's very little that is straightforward and predictable about human vision and visual perception and processing. Given the market in powerful bike lights, one would have thought that the manufacturers could have provided some evidence that their products actually increase safety. At the moment there appears to be no evidence that they do.