"Flashlight Etiquette" for Cyclists

[zespectre]

I disagree, strobes increase awareness by breaking the monotony of constant output lights.

There have been studies by several safety organizations that demonstrate a problem with that.

It has been demonstrated that a very bright flashing strobe light -especially one blinking in a steady pattern without random shifts- grabs attention and then certain segments of motorist, especially the elderly, the intoxicated/impaired, and the severely fatigued all have trouble "breaking free" and they will actually be drawn in, unintentionally moving towards the strobe rather than avoiding it.

If I can find the research papers again I'll link to them.

 

[zespectre]

Yesterday I found a related article, interesting reading

Can a Light Be Too Bright?

You have probably experienced this before: it's dark outside as you make your daily ride home when you see a small, bright dot appear in the distance. As it nears, the light becomes brighter and brighter until you're completely blinded. You now choose one of two options: keep riding forward and hope to not run into anything, or move to the side and wait until the oncoming cyclist has passed before resuming your ride.
With the current technology, many bike light companies are fighting to develop the brightest beam around and are pushing the envelope when it comes to maximizing lumens — a lumen is the measuring unit that determines the total amount of visible light emitted by a source and the main terminology used to describe how bright a light is. Examples include the Magicshine MJ-880 which features 2,000 lumens, while 1,700-lumen headlights are provided by Nitelight's Pacifier and the Gemini Olympia LED. To give a comparison, the average bicycle headlight is between 500 to 1,000 lumens. Many people, cyclists and motorists included, are starting to wonder if the "Lumen's Race" could be getting out of hand.

[See link at top for full article]

 

[Tachikoma]

What about tail lights? Let's say I wanted to use this hooked up to my brakes, to get maximum attention when I stop
and avoid getting ran over (maybe max setting only during daylight hours), would it be too much?

 

[zespectre]

Tachikoma,
A 5000 lumen red panel as a brake light.
Well, it would certainly get you attention but I'm not sure it would prevent you from getting run off the road (possibly the opposite with the wrong temper behind the wheel) and it certainly wouldn't do anything positive for Cyclist/Driver relations.

 

[Bandgap]

There have been studies by several safety organizations that demonstrate a problem with that.

It has been demonstrated that a very bright flashing strobe light -especially one blinking in a steady pattern without random shifts- grabs attention and then certain segments of motorist, especially the elderly, the intoxicated/impaired, and the severely fatigued all have trouble "breaking free" and they will actually be drawn in, unintentionally moving towards the strobe rather than avoiding it.

If I can find the research papers again I'll link to them.

I think I am one who has trouble breaking free, even when sober!

My question above was trying to discover the level at which flashing white LEDs in the daytime are too grabbing (for want of a better expression!).

Little white blinkies are quite good. But there is a guy that cycles in the opposite direction to me in the morning who has a flasher bright enough to take almost all my concentration in daylight.

I would like to know how bright that is, to have a reference level.

Torchguy, is there a way you can get someone to ride your bike towards you to give me/us an idea?
Probably, in brilliant summer sunshine 500 lm flashing is not a 'grabber'.
I have no idea under what conditions 500 lm (or any other number of lm) might be?
(BTW, I know it is really cd/m^2 that is the intensity, but for the purposes of discussion....)

Conversely - I am pretty sure constant bright lights in the daytime are noticeable without grabbing.

On a rear lights..
I had a very bright flashing rear light, and on seeing it a friend of mine pointed out that his similar light had actually caused the driver behind him to be distracted/disoriented to the point he almost hit something, so he stopped using it. I have kept the light on the bike, but only turn it on in fog. (frustratingly, it flattens batteries even when off)

I also rode behind Zac Kaplan (the recumbent guy) when he was testing to rear strobes -a bright LED one and a xenon one.
I cannot remember which way round it was, but one was too bright to want to ride behind in the day, and the other was dazzling at night. The odd thing was, the daytime dazzling one was not night time dazzling.
All I can remember is, they were different shades of red.

Bandgap Steve

 

[Bandgap]

What about tail lights? Let's say I wanted to use this hooked up to my brakes, to get maximum attention when I stop
and avoid getting ran over (maybe max setting only during daylight hours), would it be too much?

Space aliens would be crashing into each other around Jupiter if you had that as a brake light!

Why not just aim for something as bright as a car or motorcycle brake light, 400-500 lm

Bandgap Steve

 

[neonnoun]

There is a practical limit to the brightness that the average bike rider will want. It's basically limited to the batteries. The reliable and inexpensive (relative) lights only get 1-2 hours out of a set of batteries at 400-800 lumens. That's assuming they are using rechargables; perhaps 18650's even.

Above that, you have to spend a bunch of money and go with external battery packs. The cable connecting the battery packs to the lights are notoriously unreliable, so for all that money you don't even get to use them that long without making repairs.

Basically, this whole discussion is about a very small (but highly visible!) group of cyclists.

As for the "100W Watt Red High Power" brake light. LOL, it would take like 20 18650s to get any time out of it. Why not just go for a Maelstrom XM18, a red filter and then rubber band the whole thing to the back of your helmet?

 

[Bandgap]

My question above was trying to discover the level at which flashing white LEDs in the daytime are too grabbing (for want of a better expression!).
Little white blinkies are quite good. But there is a guy that cycles in the opposite direction to me in the morning who has a flasher bright enough to take almost all my concentration in daylight.
Bandgap Steve

Just for a bit of balance, that miserable old sod Bandgap Steve (me) drove home in the rain a couple of nights ago past a cyclist with a flashing front light whose intensity was perfect.

It was dusk, that most awful time for bike visibility, and the light attracted attention through the the rain perfectly.
It must have been brighter than a blinky.
And imho would have been better if it had not been flashing - but it was a perfect balance between visibility and non-grabbingness.

Wish I knew the numbers. It was not the sort of evening to pull over and ask the cyclist.

Bandgap Steve

 

[Steve K]

Yep... balance is good.. especially for cyclists!


Similarly, I've seen flashing headlights that really stood out among other traffic without being annoying, and I've seen some that just made me say "ouch!". The ones that I preferred used a slower flash rate; perhaps 2 Hz or so? The really obnoxious one that I've seen was flashing about 5 to 8 Hz (estimating). Of course, it seemed pretty bright too, so it might have been annoying even in a steady mode, but that flash rate seemed especially bad.

 

[cue003]

The true approach here should not be on the output of lights since everyone's vision is different for both day and nighttime use. It should be around proper aiming of your bike light. We talk about cars and how their lights have cutoff etc..etc... But get down level with those hid or halagen car headlights and you will have a different thought. You have to aim the bike lights correctly to reduce the in the face approach. Most people think they need to aim a bike light horizontal when they attach it to their bike. They need education on where to truly place that spot/core of the light and things would be better.

Cars lighting is fixed, bicycle lighting height has to be readjusted everytime for self contained lights since you take the light off the bike to charge it. It is a conscious effort that all bike riders/light users need to the aware of.

The nice thing with stvo is basically you install/connect you light level with the horizon and the internal light is then "angled" accordingly. This removes the guest work from each individual person for repetitive light mounting from day to day and angling their light themselves.

 

[RI Chevy]

Good point Cue! :thumbsup:

 

[N8N]

There really are no "ideal" road riding lights available today... StVZO lights are limited in the current they can draw from the hub dyno for intercompatibility, even if your particular hub dyno can output much more power. I'm not aware of any non-symmetric (e.g. flashlight like) beam lights made that aren't StVZO compliant.

I'm currently running a B&M IQ Cyo, but that light is about 5 years out of date. It works, but I wish it had a wider beam pattern. Apparently the Philips Saferide and the new B&M Luxos address that by using a more efficient emitter and redesigned optics to take advantage of the increased total light output. But they're still limited to StVZO current draw. Even the German battery lights seem to be based on StVZO designs.

When riding in pitch black conditions I'll strap a flashlight to my bars with a twofish block and use it as a "high beam" to supplement the IQ Cyo. That actually works really well. I'm ashamed to admit that that flashlight is a Task Force 3W deal... really big and heavy by today's standards for the light output but it gets the job done.

If there's any better solution than a StVZO light that I'm missing, someone please let me know... I'd love to have a higher powered alternative.

 

[Bandgap]

You have to aim the bike lights correctly to reduce the in the face approach. Most people think they need to aim a bike light horizontal when they attach it to their bike. They need education on where to truly place that spot/core of the light and things would be better.

I agree.
I have an idea that there should be a mark on the bike lights that should be upper-most (at a certain brightness setting) to make the light other-road-user-friendly.
Sadly, this will mean very bright lights have to be pointed so steeply downward that I don't think users will accept it.
Better to have a mode on light that is properly anti-dazzle, not just a round beam.

Bandap Steve

 

[Hashime]

Mounting the light lower down helps as well.

I gave a fork mount a shot and it cut down the dazzle quite a bit. The downside was not being able to see the depth of pot-holes, but a less powerful light on the bars could be used for that.

 

[Steve K]

hmmm... my experience is that a low mounted light makes it harder to keep the light out of the eyes of oncoming traffic. If the light were aimed with the same angle of elevation regardless of the mounting height, then it should shine just as much light above the horizon whether the light is mounted on the fork or handlebars.

The issue with low mounted lights is that for a given beam width (vertically), the low mounted light will illuminate the nearby road more, reducing the relative brightness of the road far away. To compensate, it is natural to increase the angle of elevation of the light. This reduces the light nearby with little or no reduction in the illumination of the road far away. However, it does put more light above the horizon and into the eyes of oncoming traffic.

With a well designed beam, this effect might be minimal. With a symmetric beam such as I use, I've had to go to fairly narrow beams to reduce the effect. Seems to work okay, but I'd be happier with a beam that was narrower in the vertical direction, and these don't seem to exist.

I will also comment that one disadvantage of low mounted lights is found when riding on rolling hills. When cresting a hill, it takes longer before oncoming traffic will see the light.

For reference, this is my set up.....

With a recumbent like this, there are limits to where the light can be mounted. Having to worry about whether my feet would hit my headlight was a new consideration!

 

[zespectre]

That's a fascinating setup.

 

[Steve K]

well, fascinating in an aesthetically insensitive sort of way...
I like to think of it as being theft-resistant.

Mounting a light to the middle of a fork that was never intended for it does have challenges. Similarly, the wiring arrangement is complicated by the fact that the SON dynamo has electrical connectors on the right and my light needs to be on the left. It is functional, though, and has been in use since 2008.

 

[subwoofer]

well, fascinating in an aesthetically insensitive sort of way...
I like to think of it as being theft-resistant.

Mounting a light to the middle of a fork that was never intended for it does have challenges. Similarly, the wiring arrangement is complicated by the fact that the SON dynamo has electrical connectors on the right and my light needs to be on the left. It is functional, though, and has been in use since 2008.

Although I admire your ingenuity, I think that having the light mounted so low is (as you have commented yourself) bad for both the rider and oncoming traffic. I would also imagine the shadow cast by the wheel would be very distracting (you appear to have mounted it to the left of the front wheel which means there will be a nice big shadow of the rim and tyre over to the right.

The only advantage I can think of for this set-up is that by being further from the riders line of vision it will show the road/trail undulations much better due the the shadows cast.

 

[Hashime]

That is a definite downside of a lower mount. When I played with it I ended up using a shrowd to cut the beam down a bit on the sides and top.

I run off the bars now, I stopped caring about the dazzle after about the third time people left their high beams on coming towards me on the rural part of that route.

Consider a cylindrical lens to get a stretched beam. I use a 10x30 on my main light as a flood. It makes a huge difference when I am on trails at night. I supplement with a 10° spot on my helmet when off road.

 

[Steve K]

Although I admire your ingenuity, I think that having the light mounted so low is (as you have commented yourself) bad for both the rider and oncoming traffic. I would also imagine the shadow cast by the wheel would be very distracting (you appear to have mounted it to the left of the front wheel which means there will be a nice big shadow of the rim and tyre over to the right.

The only advantage I can think of for this set-up is that by being further from the riders line of vision it will show the road/trail undulations much better due the the shadows cast.

With this type of recumbent, there are very few good options for mounting a light. On a second recumbent of this style (but lighter and faster), I've got a light mounted to the frame just above the crankset.....

It has the same Ledil Rocket SS lens (and XR-E LED) that I have on the dynamo light. I can aim it a bit lower, which is good. The disadvantages are that it doesn't show the holes in the road as well because it's essentially at head height, and it throws a lot of light on my feet. Oh... it also doesn't track with the front wheel, so it doesn't shine forward when making tight turns.

Back to the fork-mounted headlight.. there is a shadow from the tire/rim, but it really isn't an issue. The shadow is relatively close to me, and I really only care about things that are further away. Yeah.. I had thought it might be a problem too, but it turns out not to be a problem at all.

A buddy did do a cool headlight installation on his Bacchetta Strada recumbent. He mounted the light under the crankset, and used a little motor (scavenged from a model airplane servo) to scan the headlight left and right. Nifty and fun, but a bit more complicated than I was going for. Perhaps a better idea would be to use a linkage from the fork to swing the light from left to right?