The University of Aalborg Study on Daytime Flashing Lights forBicycles.
I know how some people dislike any statements that are based on actual
facts, but the data are pretty clear. See: https://books.google.com.au/books?id=LvthAgAAQBAJ&pg=PA168 It was interesting that in the Odense study, conducted by Reelight, Odense Cycle City and the University of Aalborg, accident rates went down by 32% with the use of daytime lights, but a cyclist's "sense of security" went up by 85%! Did they ride more dangerously because of the huge increase in their "sense of security" and still experience a 32% decline?! Another study showed that safety equipment increases an individual's dangerous behavior, so if we could find a way to encourage the use of proven safety equipment without increasing risky behavior, we'd be able to change that 32% to a much higher number. While a 32% decline in accident rates is significant, the 85% increase in the "sense of security" could lead to more cycling, which will further reduce the percentage of accidents. The purpose of this whole study was to convince the government to make flashing lights legal, since in some backward European countries flashing lights are not legal. While this change in the law could increase sales of Reelight, it also benefits every other light manufacturer that produces flashing lights, and the other manufacturer's produce much brighter daytime lights. Hopefully the results of this study will lead to dynamo light manufacturers adding a flash mode to lights that they export to countries where flashing lights are legal. It just needs to be one zero-ohm resistor that is installed or removed on the PCB. These lights almost certainly already have a micro-controller that can be programmed to do flash mode. The bottom line is that we can all agree that daytime flashing lights on bicycles are a very good idea and that greatly increase safety and that their use should be encouraged. Frank now owns one of Barry Beam's Oculus lights, so he can now experience the increased safety and increased sense of security of a daytime flashing light as well as increased visibility at night. Now I have to go cash my check from Reelight. |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Sun, 19 Mar 2017 11:53:38 -0700, sms
wrote: I know how some people dislike any statements that are based on actual facts, but the data are pretty clear. See: https://books.google.com.au/books?id=LvthAgAAQBAJ&pg=PA168 It was interesting that in the Odense study, conducted by Reelight, Odense Cycle City and the University of Aalborg, accident rates went down by 32% with the use of daytime lights, but a cyclist's "sense of security" went up by 85%! According to the above URL, it "reduced the number of crashed by more than 30%". Presumably, accidents without an associated crash were not counted. Also, the study was conducted in 2005 in Denmark, a country there cycling is far more common than in the US. The accidents were self-reported which usually means that if someone is guilty of doing something stupid on their bicycle, they are unlikely to report the incident. It's also possible that the situation may have changed in the last 12 years such as newer models by Reelight. I also don't like terms like "30% reduction". In order to make sense of that, the actual accident rates need to be disclosed. For example, out of population of 2000 participants, a reduction from 3 accidents to 2 accidents is a 33% reduction, as is a reduction from 300 accidents to 200 accidents. The former is bad joke while the latter is probably statistically significant. Which is it? The only link I can find to the original study is listed on the Wikipedia Bicycle Lighting page as footnote 8. However the links to both the original Danish and English translation are broken. Also, I would have expected to see a copy of the study on the Reelight web pile, but couldn't find anything. Duz anyone have a copy or a functional link? Oddly, the Reelight FAQ doesn't quite agree with the study: https://www.reelight.com/en/faq/ "The number of accidents is not higher when it is dark. However, the risk of being involved in a road accident is greater at night than during daylight hours. This is why bicycle lights are so important." Note that they have a backup function, that continues to flash when the bicycle is stopped: "The backup function needs to charge the first time it is in use. You need to ride the bike for 5-10 minutes for it to charge fully and so that it will flash for a few minutes after you stop." Do it thyself flashing tail light: https://dr2chase.wordpress.com/2013/12/23/lights-for-a-beater-bike/ We've also been here befo https://groups.google.com/forum/#!topic/rec.bicycles.tech/X0rymhXTgGo Now I have to go cash my check from Reelight. Such things are usually done by "loaning" you test samples of the products, and then "forgetting" to recover them. In theory, you're expected to declare the value of such samples as income for tax purposes. Payments of cash or checks are rare unless you are hired as a consultant. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/19/2017 4:02 PM, Jeff Liebermann wrote:
On Sun, 19 Mar 2017 11:53:38 -0700, sms wrote: I know how some people dislike any statements that are based on actual facts, but the data are pretty clear. See: https://books.google.com.au/books?id=LvthAgAAQBAJ&pg=PA168 It was interesting that in the Odense study, conducted by Reelight, Odense Cycle City and the University of Aalborg, accident rates went down by 32% with the use of daytime lights, but a cyclist's "sense of security" went up by 85%! According to the above URL, it "reduced the number of crashed by more than 30%". Presumably, accidents without an associated crash were not counted. Also, the study was conducted in 2005 in Denmark, a country there cycling is far more common than in the US. The accidents were self-reported which usually means that if someone is guilty of doing something stupid on their bicycle, they are unlikely to report the incident. It's also possible that the situation may have changed in the last 12 years such as newer models by Reelight. I also don't like terms like "30% reduction". In order to make sense of that, the actual accident rates need to be disclosed. For example, out of population of 2000 participants, a reduction from 3 accidents to 2 accidents is a 33% reduction, as is a reduction from 300 accidents to 200 accidents. The former is bad joke while the latter is probably statistically significant. Which is it? The only link I can find to the original study is listed on the Wikipedia Bicycle Lighting page as footnote 8. However the links to both the original Danish and English translation are broken. Also, I would have expected to see a copy of the study on the Reelight web pile, but couldn't find anything. Duz anyone have a copy or a functional link? Oddly, the Reelight FAQ doesn't quite agree with the study: https://www.reelight.com/en/faq/ "The number of accidents is not higher when it is dark. However, the risk of being involved in a road accident is greater at night than during daylight hours. This is why bicycle lights are so important." Note that they have a backup function, that continues to flash when the bicycle is stopped: "The backup function needs to charge the first time it is in use. You need to ride the bike for 5-10 minutes for it to charge fully and so that it will flash for a few minutes after you stop." Do it thyself flashing tail light: https://dr2chase.wordpress.com/2013/12/23/lights-for-a-beater-bike/ We've also been here befo https://groups.google.com/forum/#!topic/rec.bicycles.tech/X0rymhXTgGo Now I have to go cash my check from Reelight. Such things are usually done by "loaning" you test samples of the products, and then "forgetting" to recover them. In theory, you're expected to declare the value of such samples as income for tax purposes. Payments of cash or checks are rare unless you are hired as a consultant. I read 'lights for beater'. Twice. Then did a page search for coil, magnet, dynamo and battery. Found nothing. What powers the lights? Bonus question- What does the mirror do? -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/19/2017 2:02 PM, Jeff Liebermann wrote:
The only link I can find to the original study is listed on the Wikipedia Bicycle Lighting page as footnote 8. However the links to both the original Danish and English translation are broken. Also, I would have expected to see a copy of the study on the Reelight web pile, but couldn't find anything. Duz anyone have a copy or a functional link? It's not free. http://www.sciencedirect.com/science/article/pii/S0001457512002606. I'll check on Tuesday if our library or Public Works department has access to this journal. |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/19/2017 2:02 PM, Jeff Liebermann wrote:
Now I have to go cash my check from Reelight. Such things are usually done by "loaning" you test samples of the products, and then "forgetting" to recover them. In theory, you're expected to declare the value of such samples as income for tax purposes. Payments of cash or checks are rare unless you are hired as a consultant. Yes, but a couple of people in this group insist that the only reason I favor good lights is because I am getting paid by light companies. The fact that it isn't true doesn't matter to them. They will come up with any excuse they can think of to try to ignore the data. |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Sun, 19 Mar 2017 16:54:07 -0500, AMuzi wrote:
On 3/19/2017 4:02 PM, Jeff Liebermann wrote: Do it thyself flashing tail light: https://dr2chase.wordpress.com/2013/12/23/lights-for-a-beater-bike/ I read 'lights for beater'. Twice. Then did a page search for coil, magnet, dynamo and battery. Found nothing. What powers the lights? The top photo of the bicycle shows a hub dynamo on the front wheel. Directly under the photo is: "Note that there’s no off switch and no way to disconnect anything but the hub without wire clippers or a soldering iron." So, I guess it's powered by the hub. Since there's no on/off switch, it's also a daytime tail light. Bonus question- What does the mirror do? Go to: https://www.flickr.com/photos/dr2chase/11425296075 and drag the mouse around the photo. The captions for the mirror say "Acrylic mirror to keep light down towards the road" and "Aluminum angle - mirror glued to top, lights glued to front, holes drilled for zip-tie attachment to basket". The rectangular stick jammed between the mirror and basket is labeled" Vertical aiming adjustment". The cylindrical contraption is labeled "Greinacher-ish rectifier and voltage doubler in corked tube". Schematic? Nope. Other labels around the tangle of Romex electrical wire are "white wire to hub AC power", "white wire to taillight", and "Connection of rectifier to headlights, headlights to taillights, and taillights to rectifier". It's now kinda, maybe, sorta, almost, somewhat clear. If you want a hub powered tail light to light up the road, that is how it can be done. His flickr page also has his helmet mounted headlight and tail light combination: https://www.flickr.com/photos/dr2chase/with/11425296075/ Soon, everyone will be wearing an optical test bench glued to their helmet. Please remind me not to reference a do-it-thyself web page without first carefully reading it. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Sunday, March 19, 2017 at 6:56:22 PM UTC, sms wrote:
Odense My ancestor, Odin, who was worshiped as a god by the Anglo-Saxons until the coming of Christianity, lived on Odense, an island off the coast of Jutland, where the city of Odense, named for him, now stands. Of course he wasn't a god to start with. He was a warrior and a poet, but then all chiefs were warriors and were expected to be poets as well; in addition he was widely recognized as a moral philosopher and he had lots of really violent descendants, including Horsa and Hengist, who founded the British nation. They were Jutes, like Odin, but the Jutes were a small tribe, so the mass of Anglo-Saxon johnny-come-latelies just claimed them, and Odin, for their own history. The Encyclopedia Britannica, at least in the famous 11th edition which I use, got it right, but who listens to the Britannica except the truly well-educated, whose relatives probably wrote the relevant articles. Andre Jute It helps your posterity to have lots of really violent descendants PS Don't ask: I don't know if Odin cycled before he became too dignified, being a god, to ride a bicycle like the other Jutes, now called Danes. |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/19/2017 6:24 PM, sms wrote:
On 3/19/2017 2:02 PM, Jeff Liebermann wrote: Now I have to go cash my check from Reelight. Such things are usually done by "loaning" you test samples of the products, and then "forgetting" to recover them. In theory, you're expected to declare the value of such samples as income for tax purposes. Payments of cash or checks are rare unless you are hired as a consultant. Yes, but a couple of people in this group insist that the only reason I favor good lights is because I am getting paid by light companies. The remarks (generally about commission) arose because several of your websites which touted dozens of products, and had at the bottom statements something like "if you're going to buy one of these, please start from this website so I get my commission." And some of your web pages included a sort of brief resume in which you bragged about doing "guerilla marketing" in bicycle forums. Those statements seem to have been taken down now. But when they were first discovered, there were links and quotes posted here. -- - Frank Krygowski |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Sun, 19 Mar 2017 15:24:31 -0700, sms
wrote: On 3/19/2017 2:02 PM, Jeff Liebermann wrote: Now I have to go cash my check from Reelight. Such things are usually done by "loaning" you test samples of the products, and then "forgetting" to recover them. In theory, you're expected to declare the value of such samples as income for tax purposes. Payments of cash or checks are rare unless you are hired as a consultant. Yes, but a couple of people in this group insist that the only reason I favor good lights is because I am getting paid by light companies. The fact that it isn't true doesn't matter to them. They will come up with any excuse they can think of to try to ignore the data. If you arrange with Reelight to send your persecutors some free sample lights, they might be inclined to reconsider their position. The problem here is that if you are repeatedly accused of some dastardly crime against the cycling multitudes, such as accepting payola from a vendor, the mere repetition of the accusation will eventually cause it to become a truism. Anyone who searches the web for bicycle lighting recommendations will eventually blunder across those accusations. The casual reader is more likely to accept the accusations at face value than to continue reading the subsequent discussion material. You might consider writing a explanation, FAQ, or manifesto on the topic, which you can reference in future discussions on the topic. Please have them ship the bribe, errr... evaluation sample, to the address below. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Sun, 19 Mar 2017 11:53:38 -0700, sms
wrote: I know how some people dislike any statements that are based on actual facts, but the data are pretty clear. See: https://books.google.com.au/books?id=LvthAgAAQBAJ&pg=PA168 It was interesting that in the Odense study, conducted by Reelight, Odense Cycle City and the University of Aalborg, accident rates went down by 32% with the use of daytime lights, but a cyclist's "sense of security" went up by 85%! Did they ride more dangerously because of the huge increase in their "sense of security" and still experience a 32% decline?! Another study showed that safety equipment increases an individual's dangerous behavior, so if we could find a way to encourage the use of proven safety equipment without increasing risky behavior, we'd be able to change that 32% to a much higher number. While a 32% decline in accident rates is significant, the 85% increase in the "sense of security" could lead to more cycling, which will further reduce the percentage of accidents. The purpose of this whole study was to convince the government to make flashing lights legal, since in some backward European countries flashing lights are not legal. While this change in the law could increase sales of Reelight, it also benefits every other light manufacturer that produces flashing lights, and the other manufacturer's produce much brighter daytime lights. Hopefully the results of this study will lead to dynamo light manufacturers adding a flash mode to lights that they export to countries where flashing lights are legal. It just needs to be one zero-ohm resistor that is installed or removed on the PCB. These lights almost certainly already have a micro-controller that can be programmed to do flash mode. The bottom line is that we can all agree that daytime flashing lights on bicycles are a very good idea and that greatly increase safety and that their use should be encouraged. Frank now owns one of Barry Beam's Oculus lights, so he can now experience the increased safety and increased sense of security of a daytime flashing light as well as increased visibility at night. Now I have to go cash my check from Reelight. I find your research somewhat less than complete. Or to put it another way, you carefully extracted certain figures from the study and ignored major portions. Quite contrary to what you imply the simple addition of fixed daytime lights was only part of a major program to improve safety in the city of Odense which also included: "Activities: Salt on the streets instead of gravel (which gives more punctures) Lanes for bikes where cars must give way Lanes for bicylists where they don't have to stop for red light but can continue Lending of bicycle trailers for kids Lending of powered bicycles Lending of tandem bikes The police exchanging fines for driving without light, to bicycle lights The Cyclist of the year award Exhibition for Better Bikes and possibility of having the bike checked (to get ready for the summer biking season) Campaign: We are biking to work distribution of badges to people participating in the campaign Providing drinking water and bicycle pumps several places in Odense Cycle barometers (speed and amount of cyclists passing each day)" And Amazingly, it worked. "According to the police the annual number of personal injuries amongst cyclists due to accidents involving more than one party fell by 19 per cent in the Municipality of Odense from the base years 1996-1997 to the period 1999-2002, when the Cycle City project was being implemented, and by 20 per cent up to the year 2002. Thus the project achieved its objective of reducing the number of cyclists killed or injured in accidents involving more than one party by 20 per cent by the end of 2002 as against the base years 1996- 1997. The trend of personal injuries amongst cyclists due to accidents involving more than one party followed the general trend. As there has been a significant increase in the volume of bicycle traffic in the Municipality of Odense in comparison to the trend in general, the risks of cycling in Odense have thus fallen more in Odense than other large Danish cities." The moral of this little story is that there is a danger in quoting sources. Some rotten, no good, SOB, might read them. -- Cheers, John B. |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/19/2017 6:08 PM, Jeff Liebermann wrote:
snip Please have them ship the bribe, errr... evaluation sample, to the address below. When I had the first web site that looked at many different folding bikes I was getting free bicycles. But that didn't affect my evaluations and I listed the pros and cons of each model in what I believed was an honest way. Sorry, I have no free lights to send out to anyone, and no one has sent me any lights for free either. |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/19/2017 6:30 PM, John B. wrote:
snip The moral of this little story is that there is a danger in quoting sources. Some rotten, no good, SOB, might read them. Except that the Odense study compared two control groups. One with the daytime lights, one without them. So each group had the benefit or non-benefit of the various other changes you cited. It was nothing like the bogus helmet "studies" we've seen in the past where cycling rates have risen and fallen based on factors unrelated to helmets--when cycling rates fell, it was due solely to helmet laws. When cycling rates rose, they should have risen as fast as the population went up. Of course you can look at China where there are no helmet laws and where cycling rates have plunged due to other factors (private car ownership, and a boom in subway construction). |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Sun, 19 Mar 2017 18:54:54 -0700, sms
wrote: When cycling rates rose, they should have risen as fast as the population went up. Nope. If nothing changed except the population, the cycling rate should remain constant because it's based on a percentage of that population. Of course, everything else also changes, so it's unlikely to be a constant rate. "Nighttime Cycling: Accidents, Lights, and Laws in Europe" http://www.beezodogsplace.com/wp-content/uploads/2014/10/huhn2013_Nighttime-Cycling-Accidents.pdf "This suggests that the different rules have only a marginal impact on the safety of bicycle traffic in the dark. Only a small number of nighttime accidents can be clearly attributed to the lack of lights: Other major risk factors are driving or riding under the influence of alcohol, higher driving speeds on empty roads at night and impaired night vision especially in older drivers." However, the article then blunders onward under: "The importance of bike lights in accidents" which makes me wonder if this is actually a contradiction between the data collected, and the Abstract/Summary. Offhand, I would suspect that this is one of those reports, where the data is owned by the researcher, but the conclusions are owned by whomever funded the study. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Sun, 19 Mar 2017 18:54:54 -0700, sms
wrote: On 3/19/2017 6:30 PM, John B. wrote: snip The moral of this little story is that there is a danger in quoting sources. Some rotten, no good, SOB, might read them. Except that the Odense study compared two control groups. One with the daytime lights, one without them. So each group had the benefit or non-benefit of the various other changes you cited. You really, really, should actually read the actually study.... who was it that said something about engage the brain before activating the voice? Anyway, the actual study was not "One with daytime lights, one without them" but between a permanently mounted and always on flashing light and conventional bicycle lights. There was no indication of whether the conventional bicycle lights were, or were not, used during the daytime. The results of the study was "The study contributed to a change in Danish legislation whereby flashing bike lights became legal in 2005". In short an always on, flashing, light, front and rear )that you can't turn off (or forget to charge the batteries) is better than lights that you can turn off or forget to charge. The actual lights were the Reelight SL100 which is a permanently mounted light mounted at the wheel axle level and powered by two permanent magnets attached to the spokes. Reelight states, "Reelight SL100 emits 29,000 mcd (microcandela, a unit for measuring light) from the front light and 10,000 from the rear light." deleted -- Cheers, John B. |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Sunday, March 19, 2017 at 5:51:25 PM UTC-7, Frank Krygowski wrote:
On 3/19/2017 6:24 PM, sms wrote: On 3/19/2017 2:02 PM, Jeff Liebermann wrote: Now I have to go cash my check from Reelight. Such things are usually done by "loaning" you test samples of the products, and then "forgetting" to recover them. In theory, you're expected to declare the value of such samples as income for tax purposes. Payments of cash or checks are rare unless you are hired as a consultant. Yes, but a couple of people in this group insist that the only reason I favor good lights is because I am getting paid by light companies. The remarks (generally about commission) arose because several of your websites which touted dozens of products, and had at the bottom statements something like "if you're going to buy one of these, please start from this website so I get my commission." And some of your web pages included a sort of brief resume in which you bragged about doing "guerilla marketing" in bicycle forums. Those statements seem to have been taken down now. But when they were first discovered, there were links and quotes posted here. Check this out: https://academic.oup.com/eurpub/arti...enting-bicycle Don't ride in Auckland, even with a blinky. -- Jay Beattie. |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Mon, 20 Mar 2017 06:59:40 -0700 (PDT), jbeattie
wrote: Check this out: https://academic.oup.com/eurpub/arti...enting-bicycle Don't ride in Auckland, even with a blinky. -- Jay Beattie. 187 accidents among 162 participants in 6.4 years? The carnage in the streets must be awful. I would expect all cyclists to be exterminated within their expected lifetimes. If I ride for 64 years of my life, I would expect to get hit about 10 times. Maybe bicycle fashion is the problem? https://www.google.com/search?q=dazzle+camouflage+bicycle+jacket&tbm=isch -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/19/2017 11:08 PM, John B. wrote:
snip We need a double-blind study of accident rates where they use 65,536 different combinations of front and rear lumens, flashing and steady, battery and dynamo powered, performed in 128 different countries, over ten years, in a variety of lighting conditions. Until that study has been completed we can't be absolutely certain whether or not an increase in conspicuity is beneficial to cyclists, so it makes no sense for cyclists to make themselves more visible. Let's get the UN to commission this study. |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/19/2017 8:47 PM, Jeff Liebermann wrote:
Soon, everyone will be wearing an optical test bench glued to their helmet. Of course! Anything less would not be safe enough! -- - Frank Krygowski |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/19/2017 9:08 PM, Jeff Liebermann wrote:
On Sun, 19 Mar 2017 15:24:31 -0700, sms wrote: On 3/19/2017 2:02 PM, Jeff Liebermann wrote: Now I have to go cash my check from Reelight. Such things are usually done by "loaning" you test samples of the products, and then "forgetting" to recover them. In theory, you're expected to declare the value of such samples as income for tax purposes. Payments of cash or checks are rare unless you are hired as a consultant. Yes, but a couple of people in this group insist that the only reason I favor good lights is because I am getting paid by light companies. The fact that it isn't true doesn't matter to them. They will come up with any excuse they can think of to try to ignore the data. If you arrange with Reelight to send your persecutors some free sample lights, they might be inclined to reconsider their position. The problem here is that if you are repeatedly accused of some dastardly crime against the cycling multitudes, such as accepting payola from a vendor, the mere repetition of the accusation will eventually cause it to become a truism. Anyone who searches the web for bicycle lighting recommendations will eventually blunder across those accusations. The casual reader is more likely to accept the accusations at face value than to continue reading the subsequent discussion material. You might consider writing a explanation, FAQ, or manifesto on the topic, which you can reference in future discussions on the topic. If Mr. Scharf were to do that, honesty would require including quotes of his original statements saying something like "please start your purchases from my website" and bragging about his "guerilla marketing to all aspects of the bicycling community" - or whatever the precise wording was. (I wish now I'd saved a copy.) -- - Frank Krygowski |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/19/2017 8:18 PM, Jeff Liebermann wrote:
On Sun, 19 Mar 2017 18:54:54 -0700, sms wrote: When cycling rates rose, they should have risen as fast as the population went up. Nope. If nothing changed except the population, the cycling rate should remain constant because it's based on a percentage of that population. Of course, everything else also changes, so it's unlikely to be a constant rate. Exactly. Demographics change. Roads change. Traffic changes. Bicycling infrastructure changes. Mass-transit infrastructure changes. The economy changes. In Silicon Valley, the emergence of so many corporate bus systems has reduced the number of cyclists combining a Caltrain commute with cycling "the first and last mile" (or the first and last 5 miles). Get on an Apple, Google, Yahoo, or Genentech bus near your home and there's no need to deal with public transit, or the lack of public transit, anymore. But there's been a tendency of the AHZs to blame any decline in cycling on helmet laws, or helmet promotion, which of course has no validity at all, it's just Trump-like "alternative facts." |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/20/2017 1:08 PM, sms wrote:
On 3/19/2017 11:08 PM, John B. wrote: snip We need a double-blind study of accident rates where they use 65,536 different combinations of front and rear lumens, flashing and steady, battery and dynamo powered, performed in 128 different countries, over ten years, in a variety of lighting conditions. Until that study has been completed we can't be absolutely certain whether or not an increase in conspicuity is beneficial to cyclists, so it makes no sense for cyclists to make themselves more visible. Let's get the UN to commission this study. I'd have thought you'd take on the project as a volunteer. But you really should include those six foot (two meter) bicycle flags on vertical poles as part of the study. I still don't understand why the champion of "If it may possibly help" visibility doesn't use them. Or even better, sell them via his websites. Your competition is killing you! http://www.swagbrokers.com/Fiberglas...Pole-181810804 -- - Frank Krygowski |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/20/2017 1:59 PM, sms wrote:
On 3/19/2017 8:18 PM, Jeff Liebermann wrote: On Sun, 19 Mar 2017 18:54:54 -0700, sms wrote: When cycling rates rose, they should have risen as fast as the population went up. Nope. If nothing changed except the population, the cycling rate should remain constant because it's based on a percentage of that population. Of course, everything else also changes, so it's unlikely to be a constant rate. Exactly. Demographics change. Roads change. Traffic changes. Bicycling infrastructure changes. Mass-transit infrastructure changes. The economy changes. In Silicon Valley, the emergence of so many corporate bus systems has reduced the number of cyclists combining a Caltrain commute with cycling "the first and last mile" (or the first and last 5 miles). Get on an Apple, Google, Yahoo, or Genentech bus near your home and there's no need to deal with public transit, or the lack of public transit, anymore. But there's been a tendency of the AHZs to blame any decline in cycling on helmet laws, or helmet promotion, which of course has no validity at all, it's just Trump-like "alternative facts." The fact that helmet laws dissuade riding has been best demonstrated by Australian data, which showed a STEP drop in bike riding of over 30% exactly when the helmet laws were enacted. It was not a gradual drop, as would be expected from gradually changing demographics, traffic conditions, etc. The sudden drop precisely aligned with the sudden imposition of the helmet laws. Furthermore, bike share systems have become extremely popular in recent years. Some cities and nations have repealed mandatory helmets laws because of their obvious deterrent effect on bike use. (Mexico City, Tel Aviv, Anniston AL, Boznia-Hertzegovina, etc.) Very, very few cities have attempted to implement bike share systems while enforcing helmet laws, and those few efforts have been failures. (See Melbourne, Brisbane and Seattle.) And again, logic would indicate helmet mandates and promotion would have to have some dissuading effect; the only question is the size of that effect. Obviously, _some_ people will not ride if told they must wear a helmet. _Some_ people will not ride if told bicycling is so dangerous that protective headgear is necessary. How would those ever be compensated by people who say "Oh, it's that dangerous? And I'm not allowed to ride without that ugly hat? Great! Now I'm convinced to take up bicycling!" -- - Frank Krygowski |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Monday, March 20, 2017 at 2:27:30 PM UTC-4, Frank Krygowski wrote:
Snipped And again, logic would indicate helmet mandates and promotion would have to have some dissuading effect; the only question is the size of that effect. Obviously, _some_ people will not ride if told they must wear a helmet. _Some_ people will not ride if told bicycling is so dangerous that protective headgear is necessary. How would those ever be compensated by people who say "Oh, it's that dangerous? And I'm not allowed to ride without that ugly hat? Great! Now I'm convinced to take up bicycling!" -- - Frank Krygowski Amazing how almost every tpoic here eventually morphs into a helmet slugfest of for and against. ;) As far as not riding because a law says you have to do something. Well a lot of people don't want to ride a bicycle with brakes either. A lot of people do not want to have to STOP at a stop sign or red light. In short, those who don't want to ride will ALWAYS find some excuse or the other. BTW, on the weekend I rode through a small city that had some interesting signage. One sign onto a busy main road stated "NO LEFT TURNS - BICYCLES EXCEPTED" and another sign on a one way street said "ONE WAY STREET - BICYCLES EXCEPTED. Thus you have two cases where things that a drive wouldn't expect to see are permitted for bicycle riders and in my opinion that's not very safe for the bicycle rider. Cheers |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/20/2017 9:59 AM, jbeattie wrote:
On Sunday, March 19, 2017 at 5:51:25 PM UTC-7, Frank Krygowski wrote: On 3/19/2017 6:24 PM, sms wrote: On 3/19/2017 2:02 PM, Jeff Liebermann wrote: Now I have to go cash my check from Reelight. Such things are usually done by "loaning" you test samples of the products, and then "forgetting" to recover them. In theory, you're expected to declare the value of such samples as income for tax purposes. Payments of cash or checks are rare unless you are hired as a consultant. Yes, but a couple of people in this group insist that the only reason I favor good lights is because I am getting paid by light companies. The remarks (generally about commission) arose because several of your websites which touted dozens of products, and had at the bottom statements something like "if you're going to buy one of these, please start from this website so I get my commission." And some of your web pages included a sort of brief resume in which you bragged about doing "guerilla marketing" in bicycle forums. Those statements seem to have been taken down now. But when they were first discovered, there were links and quotes posted here. Check this out: https://academic.oup.com/eurpub/arti...enting-bicycle Don't ride in Auckland, even with a blinky. Interesting study, with weird results. Seemed the group that was just "occasionally conspicuous" had the lowest crash rate. "The crash risk was similar across different patterns of using conspicuity aids except that the ‘ occasionally conspicuous day & night’ group had a lower risk relative to others." [The groups were these: " 'class one was termed ‘usually conspicuous day & night’; class two was termed ‘often conspicuous during the day and do not cycle in the dark’; class three was termed ‘occasionally conspicuous day & night’; and class four was termed ‘rarely conspicuous during the day but conspicuous in the dark’."] And the authors also refer to some other studies with similarly unexpected results. (Sorry, the footnote numbers won't appear here as proper superscripts): " ...this analysis used a composite measure of conspicuity and found no significant association with the risk of crashes involving a motor vehicle. Likewise in a previous cohort study involving bicycle commuters in Portland, using lights in the dark or reflective materials _did not predict the risk of traumatic events_ (defined as a cycling event leading to injury). 16 A strong protective effect of fluorescent colours observed in our earlier (cross-sectional) analysis 15 may be due to failure to exclude cyclist only crashes. "Our study is one of very few examining the effect of cyclist conspicuity on incident crashes, but the design did not allow us to account for behaviours of involved parties and road and traffic conditions before the crash. Some case–control studies attempted to address this issue by measuring cyclists’ acute behaviour including use of conspicuity aids before a crash. A Canadian study observed that the risk of collisions with a motor vehicle was _increased_ by wearing fluorescent clothing but decreased by wearing white or coloured clothing. 17 Likewise, a UK study reported an _increased_ risk of collision or evasion crashes by using any item of fluorescent or reflective material. 18 Additionally, a recent experiment in the UK reported _little effect_ of fluorescent clothing on drivers’ overtaking proximities. 32 "Overall, evidence for the effectiveness of conspicuity aids in reducing bicycle crash risk remains equivocal. Some have argued that cyclists’ misconceptions about their conspicuity and subsequent risk compensation could play a role in minimising potential benefits. In an Australian study, cyclists overestimated their night-time visibility and occasional cyclists were more likely than frequent cyclists to do so. 33,34 There were also misjudgements on the conspicuity benefits of fluorescent vs. retroreflective materials at night. If cyclists using conspicuity aids are confident of being seen, they may be engaged in compensatory behaviour changes, e.g. cycling in more dangerous circumstances. 18" [I've underlined some phrases for emphasis.] -- - Frank Krygowski |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Sunday, March 19, 2017 at 3:27:13 PM UTC-7, sms wrote:
On 3/19/2017 2:02 PM, Jeff Liebermann wrote: Now I have to go cash my check from Reelight. Such things are usually done by "loaning" you test samples of the products, and then "forgetting" to recover them. In theory, you're expected to declare the value of such samples as income for tax purposes. Payments of cash or checks are rare unless you are hired as a consultant. Yes, but a couple of people in this group insist that the only reason I favor good lights is because I am getting paid by light companies. The fact that it isn't true doesn't matter to them. They will come up with any excuse they can think of to try to ignore the data. No worries, I do not think you are a paid shill - just deluded............... Jeff showed himself to be extremely knowledgeable of statistics and noted the chief problem with the study. They did NOT show actual numbers because Reelights could not afford to shell out hundreds of thousands of free lights.. So this study was probably confined to perhaps a thousand and the change in accidents was in fact statistically irrelevant. So taken in pure percentages and presented as if it had meaning it makes for a good sales pitch and gives some undergraduate a paper to write. |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
|
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
Do you choose your toothpaste based on how much sexier it makes you? Yes. Without question. See https://www.youtube.com/watch?v=uhD2GcXII3Q at 0:40 |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Mon, 20 Mar 2017 10:08:00 -0700, sms
wrote: On 3/19/2017 11:08 PM, John B. wrote: snip We need a double-blind study of accident rates where they use 65,536 different combinations of front and rear lumens, flashing and steady, battery and dynamo powered, performed in 128 different countries, over ten years, in a variety of lighting conditions. Until that study has been completed we can't be absolutely certain whether or not an increase in conspicuity is beneficial to cyclists, so it makes no sense for cyclists to make themselves more visible. Let's get the UN to commission this study. I really like your style of rebuttal. First ignore what the other side says since if included would demonstrate that you don't know what you are talking about, and next make up some totally ridiculous proposal and present it as what your opponent argued. Beautiful work. I applaud you. Unfortunately it does not conceal the fact that what you stated, "a comparison of bike lights versus no bike lights", was not what the Odense study tested, nor was it the results of the study. -- Cheers, John B. |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Mon, 20 Mar 2017 14:01:55 -0400, Frank Krygowski
wrote: On 3/20/2017 1:08 PM, sms wrote: On 3/19/2017 11:08 PM, John B. wrote: snip We need a double-blind study of accident rates where they use 65,536 different combinations of front and rear lumens, flashing and steady, battery and dynamo powered, performed in 128 different countries, over ten years, in a variety of lighting conditions. Until that study has been completed we can't be absolutely certain whether or not an increase in conspicuity is beneficial to cyclists, so it makes no sense for cyclists to make themselves more visible. Let's get the UN to commission this study. I'd have thought you'd take on the project as a volunteer. But you really should include those six foot (two meter) bicycle flags on vertical poles as part of the study. I still don't understand why the champion of "If it may possibly help" visibility doesn't use them. Or even better, sell them via his websites. Your competition is killing you! http://www.swagbrokers.com/Fiberglas...Pole-181810804 The various countries I have visited all seem to have rules and regulations that argue that a orange and white "checkerboard" flag flown from vehicles operating on airfields is a good thing. I well remember that when, as a young Airman stationed in Japan, one could even ride one's personal motorbike on the airfield if flying such a flag. If a checkered flag will "fend off" a big Boeing bomber it should prove equally effective in deterring a California SUV. I believe that if the State of California should mandate that every bicycle operated on the highways of the state must be equipped, and display, a (lets be reasonable here) a 2 foot square (i.e. 4 square feet) checkered flag it would immediately result in a substantial decrease in annual bicycle "accidents" and fatalities. If ridden at night the flag would obviously have to be illuminated in some manner but that is just details. -- Cheers, John B. |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Mon, 20 Mar 2017 13:54:00 -0400, Frank Krygowski
wrote: On 3/19/2017 9:08 PM, Jeff Liebermann wrote: On Sun, 19 Mar 2017 15:24:31 -0700, sms wrote: On 3/19/2017 2:02 PM, Jeff Liebermann wrote: Now I have to go cash my check from Reelight. Such things are usually done by "loaning" you test samples of the products, and then "forgetting" to recover them. In theory, you're expected to declare the value of such samples as income for tax purposes. Payments of cash or checks are rare unless you are hired as a consultant. Yes, but a couple of people in this group insist that the only reason I favor good lights is because I am getting paid by light companies. The fact that it isn't true doesn't matter to them. They will come up with any excuse they can think of to try to ignore the data. If you arrange with Reelight to send your persecutors some free sample lights, they might be inclined to reconsider their position. The problem here is that if you are repeatedly accused of some dastardly crime against the cycling multitudes, such as accepting payola from a vendor, the mere repetition of the accusation will eventually cause it to become a truism. Anyone who searches the web for bicycle lighting recommendations will eventually blunder across those accusations. The casual reader is more likely to accept the accusations at face value than to continue reading the subsequent discussion material. You might consider writing a explanation, FAQ, or manifesto on the topic, which you can reference in future discussions on the topic. If Mr. Scharf were to do that, honesty would require including quotes of his original statements saying something like "please start your purchases from my website" and bragging about his "guerilla marketing to all aspects of the bicycling community" - or whatever the precise wording was. (I wish now I'd saved a copy.) guerilla ~ a member of an irregular armed force that fights by sabotage and harassment. -- Cheers, John B. |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Mon, 20 Mar 2017 14:26:35 -0700, sms
wrote: On 3/20/2017 1:40 PM, wrote: No worries, I do not think you are a paid shill - just deluded.............. Gee, thanks. Jeff showed himself to be extremely knowledgeable of statistics and noted the chief problem with the study. They did NOT show actual numbers because Reelights could not afford to shell out hundreds of thousands of free lights. So this study was probably confined to perhaps a thousand and the change in accidents was in fact statistically irrelevant. So taken in pure percentages and presented as if it had meaning it makes for a good sales pitch and gives some undergraduate a paper to write. Anytime someone doesn't like the results of a study they try to pick it apart. Actually not. The picking is aimed at those who seize on a study and twist its meaning into something that suits themselves... or even tell lies about the basis of the test, i.e., "bicycle lights versus no bicycle lights" to justify their own arguments. (guerilla ~ a member of an irregular armed force that fights by sabotage and harassment). -- Cheers, John B. |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Mon, 20 Mar 2017 14:26:35 -0700, sms
wrote: Anytime someone doesn't like the results of a study they try to pick it apart. Actually, common practice is to first blame someone and then pick apart the argument. However, I prefer to undermine the study and let it collapse under its own weight. If "pick it apart" is an unacceptable method of debating the merits of a study, what would you consider to be an acceptable method for this newsgroup? I could use propaganda, various logical fallacies, anecdotal evidence, my personal feelings, or perhaps fabricate a contradictory study. Methinks that "pick it apart" is the same as breaking down the study into individual claims and seeing how each one holds together under stress. Perhaps it would be helpful if I explained how I analyze such studies. I've done it in this newsgroup at least a dozen times, but have never really explained how it's done. First, I find the original study. This is the most difficult part because studies are now hidden behind pay walls, revised continuously, and "edited for publication" in different lengths and forms. Once I have the original study, I try to determine who paid for it. That's because the conclusions and summary of the study are owned by whomever paid for the study, while the actual data and calculations are owned by the academics, scientists, students, and statisticians that ran the study. Often these are different or even in opposition. I then read the study in as much detail as I have time available. That's when the differences between the study and the web page announcing the study become apparent. In medical studies and surveys, I've seen claims that are quite the opposite of what the research shows, usually because the claims support a product or remedy. From this point, my approach varies depending on what I'm trying to demonstrate, prove, denounce, or evaluate. Usually, pointing out inconsistencies, gross omissions, and occasionally math errors is sufficient. In this case, I have been unable to find the study in either the original Danish or an English translation. Therefore, I have not read the original and have had to work with a brief summary from some unknown report or survey that apparently has been quoted and recycled extensively. The best I could do is point out that the percentage cited was meaningless without also disclosing the statistical population (number of participants in the test). This is hardly "pick it apart". So, I'll pick at it some more. One problem with claiming that flashing tail lights reduce accidents is that there just might not be any correlation between tail lights and accidents at all. Just because two things correlate (follow the same trends) does not mean that one causes the other. Some ludicrous examples: http://www.tylervigen.com/spurious-correlations So, how does one prove that flashing tail lights actually cause a reduction in accidents and that the 30% drop was not a coincidence? Well, one way is play the record backwards. Instead of giving out tail lights, find a group that has been using flashing tail lights for some time and take away their tail lights. If accidents increase, then there just might be a connection. Perhaps programming the tail lights so that they flash at different rates under the assumption that a faster flashing rate is more visible and therefore safer. I could dream up a few more tests, but basically the idea is to do things that test for a connection between flashing tail lights and accidents. The other part of the problem is that it's very easy to demonstrate that something is unsafe. All that's needed is one accident. However, it's impossible prove that anything is safe because there will always be accidents caused by coincidence or disconnected correlations. Have I "picked apart" your one liner sufficiently? -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Mon, 20 Mar 2017 16:13:39 -0400, Frank Krygowski
wrote: On 3/20/2017 9:59 AM, jbeattie wrote: Check this out: https://academic.oup.com/eurpub/arti...enting-bicycle Don't ride in Auckland, even with a blinky. Interesting study, with weird results. Seemed the group that was just "occasionally conspicuous" had the lowest crash rate. (...) I see one problem with the study. There's little correlation between accident crash rate and being conspicuous. The problem that drives of vehicles that hit bicyclists almost always proclaim that they didn't see the bicyclist. That might be because the bicyclist was not easily visible, but could also be because the driver wasn't paying attention, was distracted, in desperate need of corrective vision, or was under the influence of booze, drugs, or passengers. For these drivers no amount of conspicuous clothing or flashing lights will improve their driving. That begs the question of what is the ratio of attentive drivers to impaired losers? I don't know. If I arbitrarily assign a 50/50 distribution, then I'll probably find that the overwhelming majority of bicycle crashes are caused by the impaired losers. That means that visibility has little effect on the conscientious drivers, who will probably be paying attention to their driving, and little effect on the impaired losers, who will probably be immune to any improvements in visibility. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 20/03/17 16:54, Jeff Liebermann wrote:
On Mon, 20 Mar 2017 06:59:40 -0700 (PDT), jbeattie wrote: Check this out: https://academic.oup.com/eurpub/arti...enting-bicycle Don't ride in Auckland, even with a blinky. -- Jay Beattie. 187 accidents among 162 participants in 6.4 years? The carnage in the streets must be awful. I would expect all cyclists to be exterminated within their expected lifetimes. If I ride for 64 years of my life, I would expect to get hit about 10 times. Maybe bicycle fashion is the problem? https://www.google.com/search?q=dazzle+camouflage+bicycle+jacket&tbm=isch They won't hold off a New York SUV, but they may stop you getting torpedoed by a German submarine :-) https://en.wikipedia.org/wiki/Dazzle...1)_cropped.jpg |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/20/2017 11:06 PM, Jeff Liebermann wrote:
On Mon, 20 Mar 2017 14:26:35 -0700, sms wrote: Anytime someone doesn't like the results of a study they try to pick it apart. Actually, common practice is to first blame someone and then pick apart the argument. However, I prefer to undermine the study and let it collapse under its own weight. If "pick it apart" is an unacceptable method of debating the merits of a study, what would you consider to be an acceptable method for this newsgroup? I could use propaganda, various logical fallacies, anecdotal evidence, my personal feelings, or perhaps fabricate a contradictory study. Methinks that "pick it apart" is the same as breaking down the study into individual claims and seeing how each one holds together under stress. There is a tendency to nitpick little things and then to declare the entire study as worthless, when in fact, other than perhaps in drug trials, there is just not going to be a "perfect study." Yet the goal of the study was to determine if flashing lights were effective, and if so, use the data to remove a ban on flashing lights. The company that was involved in the study certainly had a vested interest in the outcome, but they are only one of a multitude of companies that are benefiting from the outcome. Yet we used to often see studies that were almost completely bogus, touted as proving something. I recall one study on cycling rates following the imposition of an MHL where those doing the study decided that they would simply not count a large group of cyclists that passed by the counting location because they didn't think that they were normal cycling traffic. That was a study to "prove" that MHLs caused a decrease in cycling rates. Yet the Odense study was actually pretty good as far as these things go, with two control groups so factors other than the presence or absence of lights cancelled out. And while it was only a 32% reduction in accident rates, the fact that 85% cyclists "felt safer" is also a positive outcome if it leads to higher cycling rates. Part of the reason that cycling rates trend up following the passing of an MHL is probably the same reason--"oh, if I wear a helmet then I'll be safe." |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Monday, March 20, 2017 at 2:29:18 PM UTC-7, sms wrote:
On 3/20/2017 1:40 PM, wrote: No worries, I do not think you are a paid shill - just deluded............... Gee, thanks. Jeff showed himself to be extremely knowledgeable of statistics and noted the chief problem with the study. They did NOT show actual numbers because Reelights could not afford to shell out hundreds of thousands of free lights. So this study was probably confined to perhaps a thousand and the change in accidents was in fact statistically irrelevant. So taken in pure percentages and presented as if it had meaning it makes for a good sales pitch and gives some undergraduate a paper to write. Anytime someone doesn't like the results of a study they try to pick it apart. If they did not want it picked apart they only had to provide the actual numbers. And they didn't. Why do you suppose that was? |
The University of Aalborg Study on Daytime Flashing Lights forBicycles.
On 3/21/2017 1:06 AM, Jeff Liebermann wrote:
On Mon, 20 Mar 2017 14:26:35 -0700, sms wrote: Anytime someone doesn't like the results of a study they try to pick it apart. Actually, common practice is to first blame someone and then pick apart the argument. However, I prefer to undermine the study and let it collapse under its own weight. If "pick it apart" is an unacceptable method of debating the merits of a study, what would you consider to be an acceptable method for this newsgroup? I could use propaganda, various logical fallacies, anecdotal evidence, my personal feelings, or perhaps fabricate a contradictory study. Methinks that "pick it apart" is the same as breaking down the study into individual claims and seeing how each one holds together under stress. Perhaps it would be helpful if I explained how I analyze such studies. I've done it in this newsgroup at least a dozen times, but have never really explained how it's done. First, I find the original study. This is the most difficult part because studies are now hidden behind pay walls, revised continuously, and "edited for publication" in different lengths and forms. Once I have the original study, I try to determine who paid for it. That's because the conclusions and summary of the study are owned by whomever paid for the study, while the actual data and calculations are owned by the academics, scientists, students, and statisticians that ran the study. Often these are different or even in opposition. I then read the study in as much detail as I have time available. That's when the differences between the study and the web page announcing the study become apparent. In medical studies and surveys, I've seen claims that are quite the opposite of what the research shows, usually because the claims support a product or remedy. From this point, my approach varies depending on what I'm trying to demonstrate, prove, denounce, or evaluate. Usually, pointing out inconsistencies, gross omissions, and occasionally math errors is sufficient. In this case, I have been unable to find the study in either the original Danish or an English translation. Therefore, I have not read the original and have had to work with a brief summary from some unknown report or survey that apparently has been quoted and recycled extensively. The best I could do is point out that the percentage cited was meaningless without also disclosing the statistical population (number of participants in the test). This is hardly "pick it apart". So, I'll pick at it some more. One problem with claiming that flashing tail lights reduce accidents is that there just might not be any correlation between tail lights and accidents at all. Just because two things correlate (follow the same trends) does not mean that one causes the other. Some ludicrous examples: http://www.tylervigen.com/spurious-correlations So, how does one prove that flashing tail lights actually cause a reduction in accidents and that the 30% drop was not a coincidence? Well, one way is play the record backwards. Instead of giving out tail lights, find a group that has been using flashing tail lights for some time and take away their tail lights. If accidents increase, then there just might be a connection. Perhaps programming the tail lights so that they flash at different rates under the assumption that a faster flashing rate is more visible and therefore safer. I could dream up a few more tests, but basically the idea is to do things that test for a connection between flashing tail lights and accidents. The other part of the problem is that it's very easy to demonstrate that something is unsafe. All that's needed is one accident. However, it's impossible prove that anything is safe because there will always be accidents caused by coincidence or disconnected correlations. Have I "picked apart" your one liner sufficiently? I don't know but significance and meaning may vary. Just read a newspaper headline about a "new drug found 70% better than aspirin". Of 3600 people over 5 years there were 2.3% heart attacks in the daily aspirin group and 1.6% heart attacks in the new new group. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Monday, March 20, 2017 at 7:42:32 PM UTC-7, John B. wrote:
Unfortunately it does not conceal the fact that what you stated, "a comparison of bike lights versus no bike lights", was not what the Odense study tested, nor was it the results of the study. But John, the whole point is that you have NO IDEA what they accomplished with a study that so obviously had such a small study group that they wouldn't even publish the size of it. You know that in statistical analysis concerning small percentages of injuries and fatalities as bicycle accidents that the study size has to be gigantic to reveal any pertinent information. So why would you pretend differently? |
The University of Aalborg Study on Daytime Flashing Lights for Bicycles.
On Monday, March 20, 2017 at 8:05:55 PM UTC-7, John B. wrote:
On Mon, 20 Mar 2017 14:01:55 -0400, Frank Krygowski wrote: On 3/20/2017 1:08 PM, sms wrote: On 3/19/2017 11:08 PM, John B. wrote: snip We need a double-blind study of accident rates where they use 65,536 different combinations of front and rear lumens, flashing and steady, battery and dynamo powered, performed in 128 different countries, over ten years, in a variety of lighting conditions. Until that study has been completed we can't be absolutely certain whether or not an increase in conspicuity is beneficial to cyclists, so it makes no sense for cyclists to make themselves more visible. Let's get the UN to commission this study. I'd have thought you'd take on the project as a volunteer. But you really should include those six foot (two meter) bicycle flags on vertical poles as part of the study. I still don't understand why the champion of "If it may possibly help" visibility doesn't use them. Or even better, sell them via his websites. Your competition is killing you! http://www.swagbrokers.com/Fiberglas...Pole-181810804 The various countries I have visited all seem to have rules and regulations that argue that a orange and white "checkerboard" flag flown from vehicles operating on airfields is a good thing. I well remember that when, as a young Airman stationed in Japan, one could even ride one's personal motorbike on the airfield if flying such a flag. If a checkered flag will "fend off" a big Boeing bomber it should prove equally effective in deterring a California SUV. I believe that if the State of California should mandate that every bicycle operated on the highways of the state must be equipped, and display, a (lets be reasonable here) a 2 foot square (i.e. 4 square feet) checkered flag it would immediately result in a substantial decrease in annual bicycle "accidents" and fatalities. If ridden at night the flag would obviously have to be illuminated in some manner but that is just details. John, how old are you? I spent four years in the Air Force in five different states and three different countries and never heard of such a requirement. I then spent three years in commercial aviation and never heard of such a thing either. |
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