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-   -   How safe is high-visibility clothing? (http://www.bikeforums.net/advocacy-safety/623722-how-safe-high-visibility-clothing.html)

daredevil 01-02-13 05:46 PM

Quote:

Originally Posted by njkayaker (Post 15112186)
One reason they are so visible is that they are all standing up and the vast majority of the spectators are sitting down.

true...and your further point is that it's not more effective than any other color?

njkayaker 01-02-13 05:55 PM

Quote:

Originally Posted by unterhausen (Post 15099549)
I have followed someone wearing a yellow jersey and it was visible from a fairly impressive distance. I'm not sure I buy into the superior visibility of lime green. I have noticed that they backed off on lime green warning signs. We are pretty well conditioned to notice yellow, and a bright safety yellow is pretty hard to miss.

The "lime green" you are talking about isn't really lime-green at all.

The "green" color ("safety green") we are talking about almost appears to fluoresce in many situations. From my observations, it's generally more visible than other colors from longer distances in dim/low-light conditions ("fluourescent orange" might be second in visibility). I suspect that there are conditions where it isn't any more visible than other colors but very few cases where it is worse and many cases where it's better.

njkayaker 01-02-13 05:57 PM

Quote:

Originally Posted by daredevil (Post 15112215)
true...and your further point is that it's not more effective than any other color?

No, my point is that it doesn't prove that it's more effective than alternatives (like "fluorescent orange" or a normal yellow). They would be much less noticible if they were sitting down.

It's well-established that it's visible (there's no point in making that argument). The question here is whether it is the most visible (your example doesn't provide an answer to that).

daredevil 01-02-13 06:12 PM

Quote:

Originally Posted by njkayaker (Post 15112253)
The question here is whether it is the most visible

In that case I'll simply refer to jputnam's post...mostly because I really like the word conspicuity! :)

njkayaker 01-03-13 01:13 PM

There's a reason that yellow-green is deemed the most generally conspicuous.

Quote:

A range of wavelengths of light stimulates each of these receptor types to varying degrees. Yellowish-green light, for example, stimulates both L and M cones equally strongly, but only stimulates S-cones weakly. Red light, on the other hand, stimulates L cones much more than M cones, and S cones hardly at all; blue-green light stimulates M cones more than L cones, and S cones a bit more strongly, and is also the peak stimulant for rod cells; and blue light stimulates S cones more strongly than red or green light, but L and M cones more weakly. The brain combines the information from each type of receptor to give rise to different perceptions of different wavelengths of light.
http://en.wikipedia.org/wiki/Color_vision

http://en.wikipedia.org/wiki/File:Eyesensitivity.png

pilate7004 01-08-13 11:27 PM

Surely the visibility of the colour of your clothing is dependent on the colour of the background that you are against, as viewed by the viewer (in this case, presumably, the driver of the car). If you are riding against a white building, bus or billboard then black might be the best colour to be seen in. The good thing about day-glow orange, green and yellow isn't that they are bright colours, it is that they are rare colours. If the city was painted bright orange and trees grew in bright yellow and green, the choice of these for cycling would not be so obvious.

Personally I don't pay any attention to what colour clothing I wear on a bike, but I always ensure that I wear something highly reflective for when everything else turns to black. This is when it matters.

njkayaker 01-09-13 08:12 AM

Quote:

Originally Posted by pilate7004 (Post 15136293)
Surely the visibility of the colour of your clothing is dependent on the colour of the background that you are against, as viewed by the viewer (in this case, presumably, the driver of the car). If you are riding against a white building, bus or billboard then black might be the best colour to be seen in. The good thing about day-glow orange, green and yellow isn't that they are bright colours, it is that they are rare colours. If the city was painted bright orange and trees grew in bright yellow and green, the choice of these for cycling would not be so obvious.

Personally I don't pay any attention to what colour clothing I wear on a bike, but I always ensure that I wear something highly reflective for when everything else turns to black. This is when it matters.

Roads are generally dark gray or concrete color. Obviously, nothing is going to work in all situations but the problem areas you describe are relatively rare (except in Dr Suesse books).

Quote:

Originally Posted by pilate7004 (Post 15136293)
The good thing about day-glow orange, green and yellow isn't that they are bright colours, it is that they are rare colours.

That isn't the only reason (there are lots of rare colors). It's because they are brighter and, for yellow-green, more sensitive to the human eye.

atbman 01-10-13 07:17 PM

Newspaper report on hi-viz and motorcyclists:
http://www.guardian.co.uk/environmen...fe-fluorescent

daredevil 01-10-13 08:11 PM

Quote:

Originally Posted by atbman (Post 15143280)
Newspaper report on hi-viz and motorcyclists:
http://www.guardian.co.uk/environmen...fe-fluorescent

Not sure I learned much....mighty wordy.

njkayaker 01-11-13 09:05 AM

Quote:

Originally Posted by daredevil (Post 15143457)
Not sure I learned much....mighty wordy.

Rough translation for you: no one thing works all the time.

daredevil 01-11-13 09:50 AM

Quote:

Originally Posted by njkayaker (Post 15144831)
Rough translation for you: no one thing works all the time.

No kidding? Well, thanks for that! :thumb:

Can I ask kayaker, what kind of tail light do you use?

rydabent 01-12-13 01:39 PM

I have a couple of floresent lime green t-shirts that I picked for for helping sag club rides. I have had more than one cyclist comment that I was very noticeable while wearing them.

christo930 01-19-13 07:35 PM

Quote:

Originally Posted by j3ns (Post 10435339)
Still, people drive cars without helmets.
Some research shows that drivers wearing seat-belts drive faster and more recklessly than those not wearing seat-belts.

Don't get me wrong here, I am sure that high-visibility clothing adds security for cyclists. I'm just interested in knowing how much. I didn't find any data on the subject, that is why I started this thread.

John Stossil found that cyclists with headgear actually caused cars to drive closer to the bikes. Also, long hair gave cyclists more room. So the more safety stuff you have, the more people will put you in danger.

Chris

cplager 01-19-13 07:43 PM

Quote:

Originally Posted by christo930 (Post 15175902)
John Stossil found that cyclists with headgear actually caused cars to drive closer to the bikes. Also, long hair gave cyclists more room. So the more safety stuff you have, the more people will put you in danger.

I've heard the "helmets cause people to drive closer" thing before. I'm not convinced, but it may be true (I've since read more articles suggesting that it's not true, but who knows).

Personally, I've found that when riding with flashing lights, I consistently get more space from drivers than when I ride without, so I disagree with your conclusion that the more safety stuff you have, the more people put you in danger.

Cheers,
Charles

009jim 01-19-13 10:35 PM

I've worked in an underground coal mine. It's completely black down there and there aren't any street lights. Everyone wears shirts with special 3-M reflective tape sewn into them. You can see a dude about a mile away just pointing a weak flashlight in that direction. I was ambivalent until I did a little test myself. It's quite remarkable. The only dilemma for me is that I commute with a backpack. I wish my backpack had the 3-M tape sewn on it.

jputnam 01-19-13 11:27 PM

Quote:

Originally Posted by 009jim (Post 15176525)
I've worked in an underground coal mine. It's completely black down there and there aren't any street lights. Everyone wears shirts with special 3-M reflective tape sewn into them. You can see a dude about a mile away just pointing a weak flashlight in that direction. I was ambivalent until I did a little test myself. It's quite remarkable. The only dilemma for me is that I commute with a backpack. I wish my backpack had the 3-M tape sewn on it.

It's simple enough to hang a flap of reflective material on the back of your backpack -- this is just 3M diamond-grade tape on some waterproof tarpaulin fabric, with a snap to clip it over one of the straps on the outside of my backpack.

http://farm7.staticflickr.com/6109/6...1cb54a5711.jpg
Reflective Flap on Backpack by joshua_putnam, on Flickr

As others have noted, there are a few statistically valid studies showing a safety benefit from high-viz, and reflective only works if the person you want to see it has a light source. So neither one is a magic bullet, might as well use both, plus active lighting, and defensive lane positioning, and maintain situational awareness.

The risk of cycling is already quite low if you don't do any of those things; do all of them an it's really a very safe activity.

jputnam 01-19-13 11:32 PM

Quote:

Originally Posted by cplager (Post 15175928)
I've heard the "helmets cause people to drive closer" thing before. I'm not convinced, but it may be true (I've since read more articles suggesting that it's not true, but who knows).

Personally, I've found that when riding with flashing lights, I consistently get more space from drivers than when I ride without, so I disagree with your conclusion that the more safety stuff you have, the more people put you in danger.

The theory behind risk compensation would suggest that motorists are more willing to put you at risk if they perceive you to be better protected against risk.

A helmet gives the appearance that your head is armored for a crash. (A false impression, of course; helmets aren't really designed for vehicle impact forces, they're marginal for simply falling off a bike. But, for purposes of risk compensation, it's the perceived risk that matters.)

A blinking light warns that you're vulnerable, but doesn't provide any appearance of protection from impact.

Thus, at least theoretically, a helmet could induce motorists to provide less clearance; a tail light that heightens the impression of vulnerability could induce them to provide more clearance.

Don't hold your breath waiting for rigorous studies of these questions.

009jim 01-20-13 03:00 AM

Quote:

The theory behind risk compensation would suggest that motorists are more willing to put you at risk if they perceive you to be better protected against risk.
Then there's my theory that motorists are willing to put someone at risk if it'd no risk to themselves. I studied this by standing on a busy road so I was obscuring the outer perts of a parked car from the oncoming motorists. As they get closer they perceive me as "easy prey" and inch themselves to a line where they will pass me and create fear. Just when they're near, I step back about a foot to expose the side of the parked car. Remarkable how many drivers get a fright and veer markedly further away from where I was standing. Not exactly the topic for a PhD but worrying!

Stealthammer 01-20-13 04:26 AM

Quote:

Originally Posted by cplager (Post 15175928)
.....Personally, I've found that when riding with flashing lights, I consistently get more space from drivers than when I ride without, so I disagree with your conclusion that the more safety stuff you have, the more people put you in danger.....

I use to believe that a solid red taillight was the most visible and safest, and that blinking was just confusing to drivers, until I tried a blinking light about ten years ago and I realized that I too was afforded more room by most passing motorists, and it even seemed to extend to using the blinking taillight during daylight hours. When I asked several co-workers who pass me often on my rides to/from work, each told me that the blinking light caught and maintained their attention better that just a sustained red glow.

I can offer no scientific analysis, but it does occur to me that more "non-natural" flashing warning lights flash for a reason, and since that has become customary in most traffic situation, people have been "programmed" to recognize the purpose of a flashing light. I have alway ridden since then with my taillght blinking and I am confident that it is a safer approach.

As for the florescent green vs bright yellow debate, again I would suggest that the florescent green used is a "non-natural" occurring color and it will stand out more than any other color commonly seen. I believe that this, and the fact that it was found to be more visible when seen through a smokey environment, is why many if not most, rescue/firetrucks used on airfields are painted this color.

cplager 01-20-13 08:49 AM

Quote:

Originally Posted by jputnam (Post 15176627)
The theory behind risk compensation would suggest that motorists are more willing to put you at risk if they perceive you to be better protected against risk.

A helmet gives the appearance that your head is armored for a crash. (A false impression, of course; helmets aren't really designed for vehicle impact forces, they're marginal for simply falling off a bike. But, for purposes of risk compensation, it's the perceived risk that matters.)

A blinking light warns that you're vulnerable, but doesn't provide any appearance of protection from impact.

Thus, at least theoretically, a helmet could induce motorists to provide less clearance; a tail light that heightens the impression of vulnerability could induce them to provide more clearance.

Don't hold your breath waiting for rigorous studies of these questions.

This is a reasonable interpretation risk compensation. I dunno how much it really does affect drivers behaviors, but if it did, this is the effect would expect. And, unfortunately I agree that we shouldn't be expecting any real studies any time soon.

Cheers,
Charles

gpsblake 01-20-13 10:45 PM

Obviously the more seen you can be = the more safe. However, I disagree with some that say yellow is a good color, I think yellow can work against you at times, especially when riding right before the sun sets, the glare from the sun will make it even harder to see yellow. Just an opinion. I prefer bright orange myself.

Looigi 01-21-13 08:04 AM

I said it before in this thread and I'll say it again, no single color will be best in all circumstances. A color that stands out the best against the background and visual clutter is what will be most conspicuous. In a straightforward example, Fluo green is not as good against light colored spring foliage as is fluo orange, which is not as good as fluo green against bright fall foliage. Yellow may be good in many circumstances, but certainly not in all.

IMO, there is no rational argument against attempting to make yourself as conspicuous as reasonably possible. What's reasonable, of course will be a matter of opinion, risk tolerance, fashion adherence, etc...

When I see a rider in drab colors, many words come to mind, but bright isn't one of them.

rumrunn6 01-21-13 09:18 AM

isn't the floresent lime green color good because even color blind people can see it?

njkayaker 01-21-13 01:17 PM

Quote:

Originally Posted by jputnam (Post 15176627)
The theory behind risk compensation would suggest that motorists are more willing to put you at risk if they perceive you to be better protected against risk.

A helmet gives the appearance that your head is armored for a crash. (A false impression, of course; helmets aren't really designed for vehicle impact forces, they're marginal for simply falling off a bike. But, for purposes of risk compensation, it's the perceived risk that matters.)

A blinking light warns that you're vulnerable, but doesn't provide any appearance of protection from impact.

Thus, at least theoretically, a helmet could induce motorists to provide less clearance; a tail light that heightens the impression of vulnerability could induce them to provide more clearance.

Don't hold your breath waiting for rigorous studies of these questions.

Bizarre.

It doesn't make sense to expect that drivers are making the calculation that it's less risky to collide with helmeted cyclists.

An alternative hypothesis is that motorists expect that helmeted riders don't ride as erratically/weaving.

Quote:

Originally Posted by cplager (Post 15177283)
This is a reasonable interpretation risk compensation.

No, it's kind of bizarre.

============

"Risk compensation" hypotheses appear to be just like the unsupported "just so" stories of evolutionary psycology.

http://en.wikipedia.org/wiki/Critici...ary_psychology

njkayaker 01-21-13 01:24 PM

Quote:

Originally Posted by gpsblake (Post 15180111)
Obviously the more seen you can be = the more safe. However, I disagree with some that say yellow is a good color, I think yellow can work against you at times, especially when riding right before the sun sets, the glare from the sun will make it even harder to see yellow. Just an opinion. I prefer bright orange myself.

If you are ahead of a driver driving into the sun, anything you are wearing is going to be largely invisible. The only reliable way to impove this situation is to add light (with a rear light). And, given the light source one is competing against, the brighter, the better.


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