drossall wrote: Car and other lights are getting brighter too. The way forward is effective limits on the intensity, design and intrusiveness of lighting allowed to any vehicle.
That makes a lot of sense. I was noticing while looking up the brightness and power consumption of car headlamps for an earlier post, that the brighter offerings were marked 'not for road use'. So I presume that upper limits on brightness are now in place?
But as a motorist as well as a cyclist, I'm fed up with being dazzled by oncoming lights.
However, that isn't going to change tomorrow - or this year, or probably this decade - so in the meantime, surely we have to use lighting that will compete enough to be seen against the dazzle! Bike lights are not going to contribute to the 'arms race' I think, because the upper end of car headlamps will surely always outshine the majority of even the brighter cycle lamps!
I am guessing this problem will not change until the advent of driverless vehicles, whose sensors perhaps won't need viciously bright beams to see where they're going.
On a related topic - I just did a calculation of the width of the foveal field of view at 200 metres. This (according to wikipedea) represents around 1.2 degrees of the visual field (
https://en.wikipedia.org/wiki/Visual_field), and by my calculation, corresponds to just over four metres width. So, looking straight down a normal road lane, approaching or beyond 200 metres, the whole lane width should be in the high acuity part of our vision.
So in the particular incident I recounted, 'problem one' in my earlier post is probably irrelevant. Vision should have been sharp across most of the lane from 100 metres distance, and the whole lane before 200m. Assuming I'm understanding the figures correctly.
I was totally focussed on searching for something in that lane, so attention diversion (problem 2) doesn't make sense.
So that leaves the 'expectation' problem that was raised a few posts ago (which I don't believe was the issue as cyclists were in my mind at the time), or simple swamping as above. So for now, I'm going with swamping as the most probable explanation.
So it is back to the level of lighting as the most likely way of decreasing risk. I think I'm going to try an experiment - have someone flash a low power front cycle lamp next to car headlights, and see at what distance the flash is detectable/obvious. Then repeat with higher power ones. That could be a start to establishing how much difference light levels actually make, and quantifying what power of light might be a good compromise for a bike in such circumstances. Collect some real evidence about this!!