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Daytime Running Light Study

Old 10-13-23, 11:07 PM
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Daytime Running Light Study

An interesting study on day time running lights.
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Old 10-14-23, 03:59 AM
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I found a study that matches the description in the video

https://www.sciencedirect.com/scienc...606?via%3Dihub

The full study is behind a paywall.
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Old 10-14-23, 07:13 AM
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Thread moved from Electronics to A&S.
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Old 10-14-23, 09:37 AM
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Originally Posted by flangehead
I found a study that matches the description in the video

https://www.sciencedirect.com/scienc...606?via%3Dihub

The full study is behind a paywall.
While the result isn't quick, I've found that emailing the author(s) directly and requesting a copy will work. More often than not the actual researchers are happy to provide a free copy of the study.

EDIT: I found it for you. I got the Unpaywall extension, and it took me straight to the PDF file.

https://vbn.aau.dk/ws/portalfiles/po...r_bicycles.pdf

Last edited by JW Fas; 10-15-23 at 12:34 PM.
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Old 10-14-23, 02:47 PM
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You can't be TOO seen!

I go a tad overkill on the daytime lighting. Front and rear. I dial it back after dark.

I'm happy someone did a real study but I didn't need convincing that the sooner a motorist notices me the better.
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Old 10-14-23, 10:31 PM
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I have dyno lights on 2 bikes now, always on and NOT blinking.
Riding on highways with hundreds of 22 wheelers half the time. NOBODY doesn't see me from a quarter mile back.
Could be the lights, clothes, bags, fenders or me sitting up most of the time. 99% give me all the extra room available in the situation. Then there's lots of times I'm the one who has to give the extra room. That's why my mirror is enormously useful.

Last edited by GamblerGORD53; 10-14-23 at 10:35 PM.
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Old 10-15-23, 04:40 AM
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Originally Posted by JoeyBike
You can't be TOO seen!

I go a tad overkill on the daytime lighting. Front and rear. I dial it back after dark.

I'm happy someone did a real study but I didn't need convincing that the sooner a motorist notices me the better.
I agree and when I’m driving I always spot cyclists earlier with powerful day lights, especially flashing lights. So they are a no-brainer for me.

Last edited by PeteHski; 10-15-23 at 10:55 AM.
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Old 10-15-23, 06:25 AM
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Yes to lights! I ride about 3,000 miles a year on NYC streets, sharing the road with the our city's cautious and caring drivers. Oh heck yes to lights.
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Old 10-15-23, 10:24 PM
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Originally Posted by JoeyBike
You can't be TOO seen!
In fact, you can, as many first responders are slowly learning. Excessively bright and/or poorly-aimed lights blind other road users, and blinded road users cannot see you. The recent trend of equipping police and emergency vehicles with billion-candle-power LEDs seemed like a good idea, but is resulting in just as many impacts and fatalities because -- to no one's surprise who has considered the matter -- indiscriminately blinding drivers does not improve anyone's safety.
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Old 10-15-23, 10:57 PM
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Originally Posted by JoeyBike
You can't be TOO seen!
Not long ago I was driving down Austin Texas. Saw what appeared to be a cutie with long hair slowly ridding a step through wearing a pink tutu and a tank top. As I passed I noted his long black beard.

Yep... wish I had not seen that one...
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Old 10-15-23, 11:36 PM
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In fact, you can, as many first responders are slowly learning. Excessively bright and/or poorly-aimed lights blind other road users, and blinded road users cannot see you. The recent trend of equipping police and emergency vehicles with billion-candle-power LEDs seemed like a good idea, but is resulting in just as many impacts and fatalities because -- to no one's surprise who has considered the matter -- indiscriminately blinding drivers does not improve anyone's safety.
I used to drive big rigs. The highway patrol parked near road construction areas for safety at night was my worst nightmare. Those blue flashing lights were awful. It was very hard to see the road. I have been using a high intensity rear flasher for around 7 years. I have two of them because one of them is more practical to charge when away from home. I am going to buy the front amber one that matches the rear. My generator set is for night and the Dinotte quad red and amber for daylight. I won't use flashers at night.
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Old 10-16-23, 01:02 AM
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Night/Day ... Flash/Steady ... I see a lot of worry about the wrong things. In the thumbnail above the rider is to the right of the fogstripe on one of the most beautiful (if narrow) shoulders I've ever seen. I'd be on that in a New York second! First Responder vehicles get hit because they are in traffic. That, and often when stopped they don't fully pull out of the path of traffic. Hint. Don't be in the path of traffic. Nothing else you can do matters.

You think its your bright, steady, daytime (and night) lights saving you? I don't run lights in the day, and I run only one f/r, tops, at night. Why am I still alive? I think it's because I don't ride into intersections without knowing that they are clear, and I stay OUT of the main flow of traffic unless my way forward is blocked. I have ZERO fear of entering the right hand lane or even the lane to the left of that, if necessary. I don't HANG OUT over there, but I am able to be there if that is what it takes.

I don't get freaked or even annoyed, if something is parked in the bike lane because for the few seconds it takes to go around them, it I hardly feel like I am in any danger. It's not your lights. Mostly its that no one really wants to kill you. But they can if you are in their way. Stay out of their way.

TL;DR: You actually don't need lights at all to be very safe out there. But if you are ever nailed and you don't have any you will be clobbered financially and may wish you didn't survive. So run the legal minimum of lighting equipment and call it very good. The rest is down to common (road) sense.
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Old 10-16-23, 08:24 AM
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Originally Posted by zandoval
Not long ago I was driving down Austin Texas. Saw what appeared to be a cutie with long hair slowly ridding a step through wearing a pink tutu and a tank top. As I passed I noted his long black beard.

Yep... wish I had not seen that one...
A daily occurrence in NOLA, especially near the French Quarter.
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Old 10-16-23, 08:29 AM
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As a driver, I prefer seeing cyclists from a distance and good lights ensure this. Hard to see how anyone could rationally argue against this.
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Old 10-16-23, 10:07 AM
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The most important safety device is between our ears. Everything else should be considered an added layer of safety. When we add layers to enhance daytime visual conspicuity, we aren't trying to catch the attention of an engaged motorist. An alert motorist will see us. We are trying to steal the attention of the marginally engaged. To that end, the more layers the better.
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Old 10-16-23, 11:01 AM
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Motorcycles didn't always have lights. They have them now and they run them day and night. When someone is looking ahead in traffic they are looking for things that can interfere with there travel. They easily Se larger objects like cars and trucks. This is what they expect to see and there brains are accustomed to this. Motorcycles, bicyclists and pedestrians are often missed when they are scanning the road. What gets people's attention, when they are driving there automobiles, is bright lights and movement. Noise can also work if the motorists is not playing there radio to loud and the emergency vehicle is close enough. There have been plenty of studies on this to prove lights are effective. When I started bicycling in the mid seventies I rarely had close calls with motorists passing to close. It has become all to common since then. I purchased my first tail flasher near 7 years ago. It had an immediate effect. Some People have better things to do while driving than drive. You can't always watch your back. Lights help with this problem.
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Old 10-16-23, 02:23 PM
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I have noticed many more riders wearing Bright Yellow Reflective Vests in the day time with or without lights on.
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Old 10-16-23, 03:47 PM
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IMO there's no rational debate against daytime lights, especially a bright, daylight visible red strobe in back. I stress the rear because I have some degree of control over potential hazards coming from front and side, but am 100% passively dependent on drivers behind me seeing me.

That said, I wonder whether we may be overselling the added safety lights may offer, and thereby depreciating other important safety considerations. IMO situational awareness and learning to "read" traffic are probably more important, and hope that cyclists who buy lights do not fool themselves into believing that just being visible is enough.
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Old 10-16-23, 03:56 PM
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Originally Posted by Rick
Motorcycles didn't always have lights. They have them now and they run them day and night.
{Snip}
Lights help with this problem.
https://injuryfacts.nsc.org/motor-ve...s/motorcycles/

The data is very clear that your claim is incorrect.
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Old 10-16-23, 04:18 PM
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Running lights at night is a no-brainer. My commute starts at 6 am, and at this time of year I've seen a few cyclist on the road without any kind of lights, but only when they are up real close to me. A few occasions they were riding on the wrong side of the road, and once they are into my field of light, it always comes as a shock. WTF! WRONG SIDE!!! GET SOME LIGHTS!

Daytime lights? Debatable whether they help. Nevertheless, I run them.
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Old 10-16-23, 04:19 PM
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The data is very clear that your claim is incorrect.
Actually it is. Bringing up the statistics vagally does not prove that running lights doesn't help. Without running lights during the day, there would be higher collision rates.
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Old 10-16-23, 04:36 PM
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Originally Posted by TC1
In fact, you can, as many first responders are slowly learning. Excessively bright and/or poorly-aimed lights blind other road users, and blinded road users cannot see you. The recent trend of equipping police and emergency vehicles with billion-candle-power LEDs seemed like a good idea, but is resulting in just as many impacts and fatalities because -- to no one's surprise who has considered the matter -- indiscriminately blinding drivers does not improve anyone's safety.
True, but off topic.
Yes, emergency strobes can and do endanger workers in the shadows. The bright light reduces visibility the same way a bright light source will darken the background in a photograph.

Likewise, a bright rear strobe will endanger you IF you dismount and walk forward and to the side of your bike.

However, no one would or could be in his own light's shadow while riding.

That said, I join you in arguing against crazy bright strobes. You want to stand out without blinding people.
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Old 10-16-23, 04:53 PM
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Originally Posted by Rick
Actually it is. Bringing up the statistics vagally does not prove that running lights doesn't help. Without running lights during the day, there would be higher collision rates.
Assertion sans data is not a meaningful contribution.
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Old 10-16-23, 04:57 PM
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Originally Posted by FBinNY
However, no one would or could be in his own light's shadow while riding.
When your light reduces intensity, you are in its shadow. This is (partly) why flashing lights are idiotic and banned in so many places for so many vehicles.
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Old 10-16-23, 06:10 PM
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Originally Posted by TC1
When your light reduces intensity, you are in its shadow. This is (partly) why flashing lights are idiotic and banned in so many places for so many vehicles.
Yes, but you're still in the same place where you were seen and accounted.

I only posted because I felt you were making a false syllogism from the very real issue of roadside workers obscured by high intensity vehicle strobes, and the issues for cyclists.

Also note that the off interval of bike flashers is short, so driver awareness is restored fast enough to ensure safety.

Personally, I'd love to see real data comparing flashing red vs. steady red on bikes.

FWIW eons ago, before NYS changed the law, I used a flashing amber rear. Stopped twice by cops because flashing amber is for stationary hazards. (before amber turn signals on cars in USA) Sent off with good wishes after I explained that I'd rather that drivers thought of me as a hazard and underestimated my speed. Flashing amber bike tail lights are now legal in NYS, though I've never seen any.

In any case this thread is about DAYTIME running lights, and I've yet to see any bright enough to cause shadows.
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