#151
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visibility of DRL
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#152
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visibility of DRL
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#153
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visibility of DRL
On Mon, 8 Apr 2019 01:18:20 -0700, sms
wrote: On 4/7/2019 5:34 PM, wrote: snip I find it strange. You keep making statements, such as "multiple studies" but for some reason you always neglect to provide any references to actual studies. If you check the Usenet archives (deja.com) you can find the links to studies on the effectiveness of DRLs. Don't limit your search to just bicycle DRLs, also look at motorcycle DRLs. You may find it hard to believe, but there are not hundreds of government funded surveys on bicycle DRLs. Are you saying that you have not "checked the archives" and thus are unable to underwrite your claims with facts? Why is that? After all one does prefer that anyone who expounds supposed "facts" has a bit more than just a loud voice and numerous reputations to justify their arguments. Or perhaps you would have us believe that you are somehow aware of some sort of secret information, only available to the initiated, and that you are now divulging these secrets to the unwashed masses? But even if there were hundreds of double-blind studies, it would be immaterial. Anytime a statistically significant survey, or a scientifically valid study is presented, you will have a small number of people that will absolutely refuse to believe it based on some excuse. That is hardly true in your case. No one is denying anything. What you are being asked is to backup your fevered claims with facts. A feat that, to date, appears to be beyond your capability. That's why there are still climate change deniers, flat-earthers, and those that don't believe that there is any benefit to wearing a helmet in a head-impact crash. The fact that companies selling DRLs for bicycles tout the benefits of DRLs, does not negate the research conclusions, but the logic you see in this thread is along the lines of "Trek states "all existing research indicates that the single best way for a cyclist to increase the likelihood of being seen by a driver is to use a flashing light that’s daylight visible." Trek sells lights with a flash mode for daytime use. Therefore anything Trek says regarding the benefits of DRLs must be false." The fact that a company sell something proves nothing except that said company wishes to market a product, hopefully at a profit. It says nothing for the usability or value of the item. You can, for one example, buy a pet rock, for $7.99, on Amazon, which comes in a ventilated cardboard box and can be attached to your computer USB port. And does absolutely nothing. -- cheers, John B. |
#155
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visibility of DRL
On Sat, 6 Apr 2019 23:22:06 +0000 (UTC), Ralph Barone
wrote: They probably could have handed out St Christopher medals and gotten similar results. True. In college in the late 1960's, I was involved in such a study. I won't mention all the particulars because it would surely produce an irrelevant debate on the topic. The test group was given a device intended to produce a specific result. The control group was given a placebo device that did nothing. The study was a double blind study where neither the participants or researchers were told which was the real device or the placebo. What only a few people knew was that both devices were identical placebos that differed only slightly in the package coloring and markings. I vaguely recall about 80 students in each group. The test ran for about 6 weeks. Participants were expected to keep detailed logs of the effectiveness of the device. After about one week, the difference in the packaging and coloring was "discovered" and duly noted by the participants. A rumor was "accidentally" leaked indicating which package was real and which was a placebo. A few weeks later, the logged results were collected and tabulated (literally on Hollerith cards), fed to the IBM tabulator, summarized by the IBM 1620 computah, and printed for distribution among the participants. The test group produced about 40% better results than the control group. So much for the value of such studies. The problem with DRL is that anyone can see that the light is flashing or not flashing. Everyone in the test group knows that they have a functional device and everyone in the control group knows that they don't have anything to test. Expected results soon turn into actual results. In other words, there's no way I could arrange a double blind study for DRL safety and the results will tend to favor the expected results. Drivel: Last week, I was driving home late in my car over my usual route. It was very dark, but no fog or rain. In the distance was a bright red pattern of about four flashing light. I couldn't tell if they were moving or stationary. I watched them carefully trying to identify if it was a road hazard flasher, bicycle, or alien flying saucer. Finally, I was close enough to see that it was a bicycle with four asynchronously flashing lights on the helmet, belt, and left/right arms. I also noticed that I had drifted across the center divider and into the oncoming traffic lanes. Nobody was in those lanes or I might have had a rather spectacular head-on auto accident. It would seem that exotic patterns of red lights are a form of distracted driving. Perhaps changing the law to allow bicycles and other human powered vehicles to use a different color flashing tail light, or perhaps a specific pattern of flashes, might be helpful. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#156
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visibility of DRL
On Mon, 08 Apr 2019 18:19:47 -0700, Jeff Liebermann
wrote: On Sat, 6 Apr 2019 23:22:06 +0000 (UTC), Ralph Barone wrote: They probably could have handed out St Christopher medals and gotten similar results. True. In college in the late 1960's, I was involved in such a study. I won't mention all the particulars because it would surely produce an irrelevant debate on the topic. The test group was given a device intended to produce a specific result. The control group was given a placebo device that did nothing. The study was a double blind study where neither the participants or researchers were told which was the real device or the placebo. What only a few people knew was that both devices were identical placebos that differed only slightly in the package coloring and markings. I vaguely recall about 80 students in each group. The test ran for about 6 weeks. Participants were expected to keep detailed logs of the effectiveness of the device. After about one week, the difference in the packaging and coloring was "discovered" and duly noted by the participants. A rumor was "accidentally" leaked indicating which package was real and which was a placebo. A few weeks later, the logged results were collected and tabulated (literally on Hollerith cards), fed to the IBM tabulator, summarized by the IBM 1620 computah, and printed for distribution among the participants. The test group produced about 40% better results than the control group. So much for the value of such studies. The problem with DRL is that anyone can see that the light is flashing or not flashing. Everyone in the test group knows that they have a functional device and everyone in the control group knows that they don't have anything to test. Expected results soon turn into actual results. In other words, there's no way I could arrange a double blind study for DRL safety and the results will tend to favor the expected results. A friend, now deceased, was in the financial research business and ran innumerable studies to determine the feasibility of things ranging (from memory) the building a copper smelter to whether refrigerates should be sold on time payment up country. One week end when we were eating pizza and listening to his jazz records a girl came by the house asking questions for a survey. My friend refused to answer her questions as he said he was aware of the purpose of the survey and that would slant his answers. Anyway, after the girl left he commented that "it is easy to design a study to prove anything you want". Drivel: Last week, I was driving home late in my car over my usual route. It was very dark, but no fog or rain. In the distance was a bright red pattern of about four flashing light. I couldn't tell if they were moving or stationary. I watched them carefully trying to identify if it was a road hazard flasher, bicycle, or alien flying saucer. Finally, I was close enough to see that it was a bicycle with four asynchronously flashing lights on the helmet, belt, and left/right arms. I also noticed that I had drifted across the center divider and into the oncoming traffic lanes. Nobody was in those lanes or I might have had a rather spectacular head-on auto accident. It would seem that exotic patterns of red lights are a form of distracted driving. Perhaps changing the law to allow bicycles and other human powered vehicles to use a different color flashing tail light, or perhaps a specific pattern of flashes, might be helpful. -- cheers, John B. |
#157
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visibility of DRL
I want a bike-mounted death ray. Please let me know if you source one of those, Andy.
I set up one of my bikes with a front hub dynamo/drum brake. Another one has had a Sanyo bottom bracket dynamo for ages. Both these bikes now sport rectified LED lights I made that are always on (though the BB dynamo is "switched" mechanically). The light on the hub dynamo bike mounts to the front axle so it grazes the road surface; it has a collimated front white LED and an uncollimated red rear LED on the same unit, both supported by supercapacitors for standlight. I can't say that the daytime running lights have any appreciable effect on drivers, but I know that the ready-to-roll quality of a bike whose lights are always on when it's being used makes me choose that one more often than I otherwise would. |
#158
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visibility of DRL
Am 09.04.2019 um 03:19 schrieb Jeff Liebermann:
The problem with DRL is that anyone can see that the light is flashing or not flashing. Everyone in the test group knows that they have a functional device and everyone in the control group knows that they don't have anything to test. Expected results soon turn into actual results. In other words, there's no way I could arrange a double blind study for DRL safety and the results will tend to favor the expected results. The only meaningful data with DLR is a "regional" test pattern. Germany investigated this a while ago, imposing DLR for cars on one island and comparing accident rates with a similar-sized control region. In both regions, the accident rates reduced by similar amounts. |
#159
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visibility of DRL
On 4/8/2019 6:19 PM, Jeff Liebermann wrote:
The problem with DRL is that anyone can see that the light is flashing or not flashing. Everyone in the test group knows that they have a functional device and everyone in the control group knows that they don't have anything to test. Expected results soon turn into actual results. In other words, there's no way I could arrange a double blind study for DRL safety and the results will tend to favor the expected results. Another issue is that the group with the DRLs will be taking more risks. It's called " “risk compensation." In the Odense study, the results would have been skewed by risk compensation. If all the riders had somehow been forced to take the same risks, the conclusion would have been different, with the riders using DRLs having even fewer incidents. |
#160
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visibility of DRL
On Tuesday, April 9, 2019 at 6:39:51 AM UTC-7, sms wrote:
On 4/8/2019 6:19 PM, Jeff Liebermann wrote: The problem with DRL is that anyone can see that the light is flashing or not flashing. Everyone in the test group knows that they have a functional device and everyone in the control group knows that they don't have anything to test. Expected results soon turn into actual results. In other words, there's no way I could arrange a double blind study for DRL safety and the results will tend to favor the expected results. Another issue is that the group with the DRLs will be taking more risks. It's called " “risk compensation." In the Odense study, the results would have been skewed by risk compensation. If all the riders had somehow been forced to take the same risks, the conclusion would have been different, with the riders using DRLs having even fewer incidents. Yes, I turn on my front flasher and say "f*** that, I'm going for it!" Then I start racing down the middle of the road, going the wrong way -- "I'm king of the world!" And with my helmet, it's no holds barred! The safety mavens around here with their five flashers and three headlights, flags, vests, etc., etc. don't seem to be doing any compensating. The most consistently crazy are the ones with the least safety equipment. -- Jay Beattie. |
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