Why cycling in high-vis may be not as safe as you think

[Kookas]

I just got my bright yellow high viz jacket. It looks pretty cool actually, even if I should've gone for a size up (I'm too tall and my arms are too long). Which sucks, because it's the right chest size. Pretty typical, though.

Though I'll say that today's the first day I've worn it, and I've already had two cars pull out really close and make me overtake them to avoid running into them, which is more than the usual 0. Hmm.

 

[GrumpyGregry]

Yawn.

nah, you want St Elijah for that.

 

[markharry66]

its yellow its bright great. For all the difference it makes you can wear a turd on a string if the they dont look when they pull out stop or get careless its going to make sod all difference in the long run, if they dont look the end result will always be the same no matter how many lights or what colour jacket you wear.

 

[theFire]

its yellow its bright great. For all the difference it makes you can wear a turd on a string if the they dont look when they pull out stop or get careless its going to make sod all difference in the long run, if they dont look the end result will always be the same no matter how many lights or what colour jacket you wear.

But you'd have a turd to throw through their window when you catch them up! Sounds like a plan!

 

[Miquel In De Rain]

Point missed totally.Im out of here.

 

[mickle]

incorrect. they do work under street lighting- not brilliantly but they do work .
Street lights are either sodium , mercury vapour or HID .
Hi viz gets a bit washed out and becomes a dull yellow or a dull orange under sodium lights even under High pressure sodium lamps. Mercury vapour lamps give a bluer/whiter light and are better for colour rendering but the daddy is HID ligghting which has a better efficacy - not efficiency as you are comparing Poawer in Watts in opposed to luminous flux.

and that bit there also proves my old college lecturer from 20+ yrs ago was right in that i will one day " need all that bollox" .

Reflectives - the clue is in the name - reflect light back to its source by use of multi facetted prisms or micro spheres, with enough scatter to reach the drivers eyes. The colour of the light emitted by the street lights has no relevance. Only the brightness.

 

[Davidc]

Reflectives - the clue is in the name - reflect light back to its source by use of multi facetted prisms or micro spheres, with enough scatter to reach the drivers eyes. The colour of the light emitted by the street lights has no relevance. Only the brightness.

Absolutely right about retro reflectives, but it's the nearly monochromatic nature and the specific colour of the street lights cause the bright colours of HiViz to wash out in street lights. The newer lights with better colour rendering are better but it'll be a long time before they're a majority.

I was out (in the car) this evening and as a result of this thread looked carefully at what was happening with visibility of a bike. I think one of the reasons very bright (in this evenings case dazzling) rear lights don't show at a distance in the countryside is the off axis typical view of them. On a country road you're not straight on to the light until fairly close to it, and the full brightness beam from the lights is narrow, whereas the reflective jacket stripes send light from your headlights (full beam when at a distance) straight back to you through a very wide angle.

Can't be sure though.

 

[PoliceMadAd]

I wear hi vis for commuting, as t shirt, fleece and big jacket are all part of my uniform, and all hi vis. But there is no clothing substitute for good lighting and defensive cycling

 

[gaz]

Absolutely right about retro reflectives, but it's the nearly monochromatic nature and the specific colour of the street lights cause the bright colours of HiViz to wash out in street lights. The newer lights with better colour rendering are better but it'll be a long time before they're a majority.

I was out (in the car) this evening and as a result of this thread looked carefully at what was happening with visibility of a bike. I think one of the reasons very bright (in this evenings case dazzling) rear lights don't show at a distance in the countryside is the off axis typical view of them. On a country road you're not straight on to the light until fairly close to it, and the full brightness beam from the lights is narrow, whereas the reflective jacket stripes send light from your headlights (full beam when at a distance) straight back to you through a very wide angle.

Can't be sure though.

Hmm... the reason that Hi-viz appears to stand out during day light is because the material reflects light rays outside of our visible spectrum into our visible spectrum, as such creating more light than everything else around it. Typically this is done with UV light.

UV light isn't emitted by any form of street lights, and as such the fluorescence of hi-viz will have no gain over any other colour of material if the washout problem is resolved, it doesn't have any benefit over other colours now during the hours of darkness.

 

[subaqua]

Reflectives - the clue is in the name - reflect light back to its source by use of multi facetted prisms or micro spheres, with enough scatter to reach the drivers eyes. The colour of the light emitted by the street lights has no relevance. Only the brightness.

exactly my point above , the colour rendering of hi viz was what i was explaining . reflectives work with even a tiny amout of light. reflectives i have no problem with .

 

[Kins]

My to old running jackets have high Vis panels as opposed to being totally dayglo yellow and look ok. I wear a reflective bib though when its gopping outside or riding the lanes at night, combined with lights.

 

[Cyclopathic]

I never seem to see any hi viz helmets. Would that be uncool squared or just twice as uncool as hi viz or a helmet?

 

[summerdays]

I never seem to see any hi viz helmets. Would that be uncool squared or just twice as uncool as hi viz or a helmet?

I have .... and even worse ... the hi-vis helmet covers that look as if you have a shower cap on your head!!

 

[Cyclopathic]

What about a helmet that flashed or throbbed if you will?

 

[Davidc]

Hmm... the reason that Hi-viz appears to stand out during day light is because the material reflects light rays outside of our visible spectrum into our visible spectrum, as such creating more light than everything else around it. Typically this is done with UV light.

UV light isn't emitted by any form of street lights, and as such the fluorescence of hi-viz will have no gain over any other colour of material if the washout problem is resolved, it doesn't have any benefit over other colours now during the hours of darkness.

I've never been aware that HiViz fabric contained UV fluorescent dyes, but if it does, as you say, then that would certainly help make them useless at night!

The ultimate answer to the problem of drivers not noticing other road users is to do away with them and use the driverless vehicles now being developed!