I wonder if B&M have good illustrations of their beam patterns? They are a lot like automotive lights... they try to put most of the light onto the road 50 or 100 feet (or more?) ahead of you where it can do some good. Very little is allowed to be above the road and shining into people's eyes. With modern car lights, they have gotten good at creating a sharp cut-off at the horizon, to the point that if the car hits a bump or goes over a small hill, the high intensity part of the beam will be shining into the eyes of oncoming traffic and really blinding them.

My own headlights don't have the benefit of this sort of technology, and are just round beams. Not ideal, but available. There are datasheets for the optics that I use, such as the Ledil "Heidi" optic. It is used with a small LED, and comes in a few versions with different width beams. The ones that I chose have a narrow-ish beam, where the intensity of the beam has fallen off to half of the peak intensity by the time you get to 4 degrees off from the center. This is how the datasheet shows it...

https://cimg4.ibsrv.net/gimg/bikefor...fe12093edd.jpg
There's not a ton of info on bike light beam patterns. I know that Peter White has put a fair bit of effort into taking pictures of the beams of the lights that he sells.

Steve in Peoria

I also have a Hypershot, and have also had a fellow cyclist exclaim that it was too bright.

When it is in steady-on mode, you can adjust the output level so that it's not blinding. The controls are not at all obvious—something I dislike about the light.

There are taillights out there that paint a "lane" on the ground, which may improve your conspicuity (Lezyne has this, I'm pretty sure I've seen others). There are also illuminated cuffs you could use if you're into that sort of thing

During daylight hours brighter is better. my intent is not to spread the light on the road. It is to be seen by cars from a distance. I need that distance because people have other things to do than drive while they are moving down the road in there motor vehicles. Laws against illegal cell phone usage have little effect on people who habitually text while driving. Being seen by traffic approaching from the rear is my main concern. Bright lights with quick movements are better at getting the attention of approaching motorists than florescent clothing. My tail flasher is bright enough that people can still see it during that annoying time twice a day when the sun is low and in your eyes.

I have a cygolite that has what I call "throbbing" mode that never fully goes dark. I have definitely seen riders with a flasher that does go dark and it can be pretty disorienting.

I'm not sure how you can hit a cyclist on skyline drive since the speed limit is 35mph, but we all have our special talents.

I've got a Light and Motion Vis 500 that has a low power "be seen" mode that is sort of like this... I think of it as a sinusoidal change in brightness. It goes through 7 cycles of medium to dim brightness, with a couple of quick strobes of "bright". I guess that strobe is to get people's attention, and then the varying brightness just keeps their attention? I've seen motorcycles with a similar change in brightness. At first I thought that it was just a loose headlight mount, but then I read about a circuit that would create this effect. Personally, I liked it.. it got my attention but wasn't annoying.

Steve in Peoria

I know the left button is for on and off and changing modes. I know the right button is for adjusting within a mode. I cannot figure out how to adjust the brightness of the steady mode. The documentation does not help.

My Hypershot 350 was stolen last week, so I have a new one, same model.

Use the right button while in steady mode.

My first sentence. I was driving.

This. Press and hold. Once or twice.

I know you were driving. I've read the first sentence. I'm just pointing out that it's a bit of a surprise that a cyclist (you), while driving, is doing the things cyclists always complain about when talking about other drivers eg. dangerously close passes. Everyone is going on about 4-5 feet distance/fully using the opposite lane and here you are dropping a story of your own bad driving and blaming the cyclist 'you didn't see, officer'.

People have a tendency to steer toward the thing they are trying to avoid hitting.

I've heard that said, but I have not heard any stories of that happening. Could it be urban legend?

I could imagine that some bike taillights might make distance and velocity hard to judge. I think Germany believes that flashing lights fall into that category and that's why they're illegal there. I'm not convinced.

Bicyclists really need to think about how visible they are. Or aren't.

Last summer on a 200k, there were three of us in a group. We had to do a detour on a very busy road with narrow shoulders. I was the only one wearing high vis jersey and I was the only one with taillights, so I volunteered to follow the others.

Photo below is ten years old, I was on a bike tour. My touring buddy was ahead, I took this photo simply because it fits the discussion, in and out of shadow on a curvy winding road, I had both of my taillights on. Some of the thorn bushes that were encroaching into the traffic lane were thorn bushes.


https://cimg2.ibsrv.net/gimg/bikefor...01cf10315a.jpg

On this road a driver could easily come around a curve and find themself three or four seconds away from a bicyclist. And in intermittent shade and sun, your eyes are always adjusted for the wrong lighting.

My understanding is that this is because they are looking at the thing they don't want to hit.
I've read advice for cyclists that if they are trying to avoid a pothole, dead racoon, whatever... they should look at where they want to go and not where they want to avoid.
Seems reasonable.

I've mentioned my experience of nearly getting hit by a car approaching me from behind. It was night, there was no other traffic, and there was no reason for the driver to not just go around me. I saw him in my mirror and could tell he wasn't pulling to the left. I was moving off of the road and onto the shoulder when he went by and knocked off my left pannier. He came back to check on me, and during our discussion, he mentioned that he saw my tail light. My guess is that he was staring at the tail light and just drove towards it. I think that has been the explanation for people driving into police cars that are stopped at the side of the road. People start looking at the car and drive towards it.

... oh... almost forgot. I was riding a recumbent on a back road on a quiet weekend morning. I was going up Santa Fe road, and a car was approaching from the other direction. He was looking at me and drifting across the road and headed towards me. I signaled for him to get back on his side of the road, and he sort of snapped out of his trance and moved back over. Was I imagining that he had a sheepish look on his face??

These examples lead me to think that bike lights should be bright enough for people to notice you, but not bright or weird enough to make people curious about them. You don't want people looking at the light more than a second or so.

Steve in Peoria
(disclaimer: this data is clearly anecdotal and should not be considered conclusive)

I believe that humans tend to steer where they look. Previous experience mostly in off road motorcycle racing I was taught to see the line that was rideable not the obstructions. That isn't generally as intuitive as you might think and requires some mental training. I found the training served me well in other sports and activities including bicycling especially mountain biking. The context was threading the way through a sea of obstructions, but I think it applies to hitting a single obstruction as well. The term for it is target fixation and I think there has been some study of it. Not sure if there is any real peer reviewed study or not.

Is there a thorough study on the history of the phrase "target fixation"?
I only ask because I know of a fatality that was literally due to target fixation. When I was working on aircraft in the Marines, our squadron lost a pilot due to fixating on the target a little too long during a bombing run. This was the era of dumb bombs. This means it was also the era of true marksmanship when getting a bomb on target relied on the pilot's skill. The pilot had to fly a certain dive angle at a certain airspeed, and then release the bomb at a certain altitude. In fact, there were tables of data for each type of bomb so that you could select different dive angles. Kinda neat to look at...

https://live.staticflickr.com/3371/3...5f5474_b_d.jpg

and just for context, this is one of our aircraft coming back from a practice session. The aircraft was dropping the little 26 pound practice bombs and firing 2.75" unguided rockets (I might be wrong about the practice bombs, but that's what was most probable).

https://live.staticflickr.com/3355/3...6997bb_b_d.jpg

Anyway... our squadron lost Lt. Murphy to target fixation. He was a student pilot, and waited too long to start pulling up after releasing the bomb.

There is a Wikipedia page on target fixation.
It is broad enough to include pretty much any instance of running into whatever you are looking at, but does say that it started with instances like Lt. Murphy.
"Target fixation is an attentional phenomenon observed in humans in which an individual becomes so focused on an observed object (be it a target or hazard) that they inadvertently increase their risk of colliding with the object. It is associated with scenarios in which the operator is in control of a high-speed vehicle or other mode of transportation, such as motorists, fighter pilots, race-car drivers, paragliders, and motorcyclists.[1] In such cases, the observer may fixate so intently on the target that they steer in the direction of their gaze, which is often the ultimate cause of a collision.[1] The term target fixation was originally used in World War II fighter-bomber pilot training to describe pilots flying into targets during a strafing or bombing run.[2]"

Steve in Peoria

People here are explaining why it COULD happen that a driver aims for the object they are hoping to miss. Steve's is the only story I've heard of it happening, but it doesn't seem like it would happen much. I do agree that there is such a thing as too bright, though it's hard to determine that.

I saw a nice setup on an ebike this week, but it's not practical for a human powered bike. There was a horizontal bar with two taillights about a foot apart. One second, they were both off, the next second they flashed about ten times per second. It alternated this way. In the middle (between those two lights), a third light was steady-on. The steady light was brighter than the two edge lights. Blinking is an attention grabber, so blinking lights don't need to be super bright.

I wear reflective trouser bands when I wear long pants. I don't usually wear the trouser bands when I'm wearing shorts, and maybe I should. I'm told they're a smart thing to have, though you really never know when headlights will reflect against stuff like this and when they won't.

I have, in the past, run a Nite-Ize spoke light in my rear wheel. It's a fantastic attention grabber even though it's not bright at all. The trouble is that it requires two CR2016 cells. They last half as long as CR2032 cells, and they cost more. And I have to turn this on and off. I believe in compromise, and I feel my routines for on and off the bike are already long, so I don't often use the spoke light. My commute is only about 30 minutes long.

"target fixation"

When I was commuting by car (now retired, no longer commute) I often saw bicyclists with pedal reflectors at a good distance away when I was on dark residential streets without a lot of other lights to distract me.

I do not have pedal reflectors, for that reason I put amber reflective tape on my crank arms. Not as good as pedal reflectors, my crank arms would only be reflective when they are nearly vertical, but better than nothing. Only on the sides of the crank arms that you see from front or rear, not on the sides since most of my bikes have reflective sidewall tires.

Two photos, first without camera flash, second with camera flash which lit up anything reflective. The two crank arms and two taillights were much brighter in second photo. This was daylight, so does not look that effective when I took the photos, but I suspect much better at night.

https://cimg2.ibsrv.net/gimg/bikefor...f4f20bc145.jpg

https://cimg3.ibsrv.net/gimg/bikefor...e5e8dd20b3.jpg

I also have reflective tape on my crankarms. Seems like a decent approximation of pedal reflectors (or even pedal lights—Redshift makes light-up pedals). Also a fair amount of reflective tape on my rims, which won't help if the motorist is dead-ahead or dead-behind, but are visible when there's a bit of offset. The taillight I'm currently using is a Lezyne "strip" that has 5 LEDs in a row, and I have them lighting up in a scrolling pattern, so there's a bit of movement without a change in overall brightness. I've seen other taillights that have some kind of scrolling pattern.

I dislike ankle cuffs, but for night riding, I do have socks with reflective dots.

Good ideas, folks. Now I'm thinking about adding reflectivity to clothing. I was able to wrap yellow reflective tape around my pedals, and I suspect it's as good as pedal reflectors.

I once used iron-on reflective tape on the backs of my gloves, and I made arrows out of it hoping it would be a kind of turn signal. I have no idea how visible it was. I think I should do it again since of course my gloves are black.

Driving back from Austin Texas we passed a Social Night Ride group down town. We were stopped at a light and one bike was lit up so bright it was like strobe lights on his bars. I literally had to shield my eyes before driving on. I can surly see the need. And not just bicycles. Scooters, runners, skaters too should use lighting. I still think that reflective clothing is a must and lighting second. I have noted that having two rear lights helps with depth perception on approaching vehicles. I have also noted that those reflectors on the pedals and those stupid reflectors in the spokes really do work. I like using the ankle reflective bands and I use reflective tape on my spokes instead of the standard plastic reflectors.

One of my biggest worries are those drivers who are subconsciously attracted to bright flashing lights like moths to flame.

Looking forward to seeing what you come up with...


https://cimg7.ibsrv.net/gimg/bikefor...59446eac5b.jpg
Sure glad we are past these days!

There is a reason that Randonneuring requires reflective ankle bands at night, along with reflective clothing, both front and rear.

A friend of mine decided to use reflective ankle bands on our last tour, but his rear panniers obscured the ankle bands, which were effectively useless.


https://cimg7.ibsrv.net/gimg/bikefor...9953f1e4bd.jpg

ACA issues every rider on their tours a triangle that is partly reflective. I put that on my left pannier when I tour, even if it is not an ACA tour. The yellow part of the triangle is reflective.

https://cimg0.ibsrv.net/gimg/bikefor...6b557fcac9.jpg

I think that drivers give me a bit more room with that triangle on the left side compared to centered on the bike. In my example, the triangle partly obscures the reflective ink on the panniers, but the orange in the triangle is mesh so the reflective print on the pannier is still partly visible.

Good thoughts.

You can put a reflective band on your knees, and it might be somewhat visible above your panniers.

For my commuting i use night and day a rear led light by Buchel (modl:Micro Leno Cob) , with stop sensor (that works quite well).
During my ride during when ther is no natural light i also use two mini red led that i screwed in the rear rack .
The two mini led can blink , the Buchel no.