Mathematical analysis of how much headlamp shining where is too much

[Andre Jute]

Analysis of Bicycle Headlight Glare

Joe Riel, Aug 2013


Abstract
--------
Computes the maximum illuminance generated by a bicycle headlight in
the eyes of oncoming traffic, both automobiles and bicycles, and
estimates whether a typical battery powered, symmetric-beam LED bicycle
light, with no optical cutoff, presents a problem.

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https://groups.google.com/forum/#!topic/rec.bicycles.tech/yph122UXH7M
Reminds me of the glory days of RBT, now a sink of dissension, but back then a haven of such a technical efflorescence that there was actually a guy who once a week (once a week!) indexed all the great technical pieces and threads there were back then. We can quibble about whether Joe gets it right or wrong, but this is surely the right way to proceed as a first approximation.

[Danneaux]

Reminds me of the glory days of RBT...

Me too, Andre; nice to see this sort of thing again.

The SMF Forum software sometimes breaks links if regular expressions are used, requiring a separate cut-and-past to view the link.

For those who wish a direct-click link, here's a TinyURL:
TinyURL: http://tinyurl.com/pya2l67
TinyURL with preview to check authenticity: http://preview.tinyurl.com/pya2l67

Best,

Dan.

[Andre Jute]

For those who wish a direct-click link, here's a TinyURL:
TinyURL: http://tinyurl.com/pya2l67
TinyURL with preview to check authenticity: http://preview.tinyurl.com/pya2l67

Thanks, Dan.

I don't mean to imply by positing a link to the article that I necessarily agree with Joe Riel's conclusions. I just like a proper engineering analysis as a basis for civilized discussion: let's agree the formula as physics before we start discussing the discretionary constants! In fact, I think some assumption has gone wrong because everyday (or every night) experience tells us that rather limp lights like Joe is talking about aren't much chop against car lights. But I have to do tax accounts, so I don't have time to chase down the precise point of slippage.