Light, Too Bright?

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Pierce
Participant
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I’ve gotten into at least two arguments with motorists regarding my flashing bike light (which at 500 lumens isn’t even the brightest around) and often get people flicking their high beams at me as well

I’m wondering if I should refrain from using the strobe or maybe use it sparingly. Thoughts?


Mick
Participant
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I find bright light pointing at my eyes irritating as hell. Blinking even more so.

I had to stop on the panther hollow trail once because someone had their bright bike light pointing directly at my eyes. I literally couldn’t see the trail in front of me.

I’m guessing you could make it less irritating, but still quite visible, just by pointing it down a little.

If it is that bright, it probably would be best not to blink it at night (unless you point it way, way down).

One problem with bike lights is that they are close to being a point source – a little more light area would be better.


gg
Member
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Point it like a low beam light would be, slightly downward and I would expect the people flashing will stop. Maybe you just have the light shooting too far out? 500 is bright if it is hitting someone’s eyes.


bear250220
Participant
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if i were driving id thank you for having a light


mjacobPGH
Member
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I’ve definitely seen bikers with lights that are so bright it is very hard for me to gauge where exactly they even are because I can’t even look in their direction. However, I don’t know what level these lights are compared to yours and a very bright light would be especially helpful in weird lighting conditions like dawn, dusk, and dreary weather.


jonawebb
Participant
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Just my opinion: I really don’t like the bright flashing lights. Leave it on steady.


pearmask
Participant
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I know opinions on this stuff vary widely and that the data on visibility of flashing vs. steady lights is inconclusive. For what it’s worth, I would personally say
A. I vastly prefer steady lights on oncoming vehicles: I’m extremely sensitive to strobe-y lights and become really disconcerted very quickly when I’m stuck looking at them
B. I’d rather have steady lights on my own bike both because the strobe-y effect in front of me drives me absolutely nuts and also because they are more helpful for me in terms of seeing what’s in my path
C. I do run my similarly-bright light flashing occasionally in sketchy traffic situations, but only during the day, and generally pointed somewhat downwards

I also run a light that maxes out at 500 lumens, and even when I run it on the lower two of its four steady settings, people still find it to be obnoxiously bright. I almost never actually run it at 500 lumens, both because I figure blinding people isn’t in my own best interests and because it makes the battery die waaay faster. Sometimes I feel bad when people remark on how bright it is, and sometimes I just don’t care and do whatever I need to do to be able to see and be seen.


neilmd
Member
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I dunno. I use an RIM 500 lumen but usually at 300 L setting and also a blinking white LED. I use the two of them for 2 reasons. First, the RIM light can be a little flakey and it sucks to have everything go black, so it is nice to have a cheap backup. Second, my sense is that the combo of a modestly bright steady light and a flash on top of it gives a strong signal to traffic that I am a cyclist but reduces the annoyance of the strobe effect. This is based on no data.


RustyRed
Member
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It was through this thread ( http://bikepgh.org/mb/topic/how-bright-is-too-bright/ ) that I learned where to get headlamps with a cutoff so I’m not blinding oncoming motorists and cyclists.
I have a B&M IXON IQ. It’s 50 Lux and I’m not sure how that translates to lumens, but it pumps out a lot of light.
$60
http://www.peterwhitecycles.com/b&m.asp


UnrealMachine
Member
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Can anyone reference a single incident where a blinking bike light caused a trafffic accident? Ever? I can reference several thousand incidents where a motorist “never saw” the cyclist that they crashed into and killed. Even school buses now use bright flashing lights to get the attention of other motorists. It should be noted that lots of lights are now using a pulse pattern on flash mode instead of a strobe pattern, which are less ‘annoying’, but still way more noticeable/useful than a steady beam.


reddan
Keymaster
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Can anyone reference a single incident where a blinking bike light caused a trafffic accident? Ever?

No, but “never caused an accident” isn’t quite the gold standard for usability.

At a practical level, rapid changes in light level “greatly impair vision“; this applies not only to oncoming motorists, but also those of us who happen to be pedaling or walking nearby. I can attest that oncoming high-intensity blinking lights encountered on the Jail Trail once left me so unable to see that I had to stop my bike, as I’d lost sight of the pedestrians a short distance ahead.

I think flashing modes are great in daylight; they’re attention-getting (albeit sometimes obnoxious), and don’t cause enough contrast to screw up someone’s vision. I’d strongly recommend against using them at night, unless you’re talking about a very low-powered “be seen” light.

The Bike Light Database FAQ has a bit of info and some links, for those who are interested.


pearmask
Participant
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Forgot to mention that I am also rather fond of the obnoxious-but-steady-handlebar-mounted-primary and dinky-battery-powered-fork-mounted-blinky-secondary setup, especially for long rides out on unfamiliar highway-ish roads where people might not be expecting to see bikes.

Running probably a 100-200 lumen steady front light, I basically never have issues with people seeing me from head-on angles (e.g. with people turning left across traffic in front of me). Peripheral angles are another story, but front lights alone don’t solve that (basically nothing does when people aren’t attentive, given some of the wrecks and close calls I’ve had when I looked like a Christmas tree)


Pierce
Participant
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“Can anyone reference a single incident where a blinking bike light caused a trafffic accident?”

I don’t know if my light *caused* the accident, but I was left hooked by a guy when I had a flashling light that I think maxed out at 250 lumens. He said he didn’t know where I was going :/

I also don’t like flashing/especially bright lights on trails and usually change my mode in that scenario. The consensus here is swaying me against using the strobe by default at night…


Drewbacca
Participant
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“I have a B&M IXON IQ. It’s 50 Lux and I’m not sure how that translates to lumens, but it pumps out a lot of light.”

That’s a ton of light. I’d say that my 15 Lux dynamo and my 300 lumen cygolite put out about the same… totally subjectively speaking.


srpit
Member
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I like Reddan’s comment above. I try to use the flashing mode during the day and switch to steady once it gets dark.

Another issue with flashing lights is that they can be more than just annoying, they can also trigger seizures and/or migraines for some people, so it is kind of important to use with caution at night when the contrast is so pronounced.


cowchip
Member
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I Do a good bit of night riding and i use the flash until just after dusk and then switch to a steady low beam on handlebar . I have found that a small light low output mounted on my helmet works well as a be seen light because if you look at the car the light is pointed at them , On the trail i switch on the crazy bright creed on low and light it up ! people will get blinded sometimes but with care at passing it is not much of an issue .


edmonds59
Participant
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My intuition seems to agree with others – moderate light on blink for visibility and a bright pointed down to actually see the road.
I have a cheap Cateye that’s probably not more than 100 lumens, on blink during the day that seems to have a noticeable (positive) effect on the behavior of oncoming drivers, in terms of turning and waiting for me. With a Niterider 650 used at dark, pointed down, to see where I’m going. From what I’ve experienced, the illuminated road and surroundings gives other road users as much useful visual cue as the light source itself.
Though I have no evidence, I can’t intuitively think of much advantage to a super bright light flashing into oncoming peoples eyes, peds, bikes, cars.


Mikhail
Member
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For those who is interested…

1 lx (lux) = 1 lm (lumen) per square meter.
1 lm (lumen) = 1 cd (candela) per 1 sr (steradian).
1 sr — it’s a way to measure angles in 3D space. Think about cones. The full sphere has 4Pi steradians.

Luminous flux differs from power (radiant flux) in that luminous flux measurements reflect the varying sensitivity of the human eye to different wavelengths of light, while radiant flux measurements indicate the total power of all electromagnetic waves emitted, independent of the eye’s ability to perceive it. In other word Luminous flus is weighted radiant flux.

Dan’s reference has also nice explanation:

What do lumens, candlepower, and lux mean? How are they measured?

The three primary brightness units are Candela (luminous intensity), Lux (luminous flux per area, aka illuminance), and Lumens (luminous flux).

Candela measures absolute brightness at a point. In other words, it measures the amount of brightness going in only one specific direction. This unit is sometimes used to define maximum brightness of a light. The value for candelas is the same regardless of distance from the light, but will be different depending on the angle from the light.

Lumens measure total luminous flux, in other words the total output of a light source in all directions that it points. If you were to integrate the candelas measured in every direction around a light source, you would get lumens. Lumens are measured using an integrating sphere, a scientific instrument that uses a reflective sphere to normalize the light beam and measure its intensity.

Lux is lumens per area. If you project a light onto a surface and add up the total amount of light hitting it and divide by the area of the surface, you get lux. The brightness in lux depends on the distance at which you measure it. Illuminance is inversely proportional to the square of the distance, so in order for lux to be a useful measurement you must know the distance at which it was measured.

Lumens are the most commonly reported value for bike light brightness. Many manufacturers use an “estimated” or “specified” brightness based on the LED’s specifications at a certain power level, but the actual brightness will depend on the circuitry used, how efficient the light’s optics are, the temperature the light operates at, and the quality of the LED. Many lights’ claimed lumens are 10-40% higher than the actual brightness. The ANSI FL1 Standard specifies a specific, repeatable method for measuring the brightness of a flashlight or bike light. Lights certified by the manufacturer with the FL1 Standard are marked with an “FL1” logo on the Bike Light Database.


Mikhail
Member
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I try to stay with solid light on main light during night and always two small blinkies: white under bar and red under seat. I usually partially cover my bright light using my left hand when I see cyclists on trail after dark.


sew
Participant
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I pass a guy on the way to work regularly that uses a strobe front light. It catches my attention from 6 to 7 blocks away without being annoying or blinding when I get closer. It might be an adjustment issue.


StuInMcCandless
Participant
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When I’m sitting behind someone at a traffic light, I make a point of turning the handlebars a bit to avoid blinding him/her. I run two front lights, the lesser one blinks, the better one on solid. Both are pointed slightly down so I can see 20 to 80 feet in front of me. The blinking one goes to solid when I’m on a trail or descending a grade.


ajbooth
Participant
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I have a NiteRider 650 on my handlebars, and run it blinking all the time. I point it slightly down. I also turn my handlebars as you describe Stu, unless the driver in front of me has pulled some a-hole maneuver to get in front of me. On those occasions, I aim for the rear view mirror.

I’d had several “your light is too bright” comments, to which I reply in one of two ways: “You saw me though, right?” or “There’s no such thing as too bright.”

My light is visible for about four or five city blocks…having been hit 6 years ago by a driver who claimed he didn’t see me (in the daylight, because you know I came out of nowhere) I never want to hear “I didn’t see you” again.


jonawebb
Participant
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I don’t think white flashing bike lights cause seizures. There are claims of that on the Internet, as about everything, but the medical information states that seizure-inducing effects happen at a higher flash rate than these lights use (five to thirty times per second).
Migraines are a different issue, of course.
I’m glad it sounds like Pierce will stop using his flashing mode at night. One less annoying light.


andyc
Member
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I once went by a guy with both a red and a white blinking light on the front.

That was probably the worst “offender” I have seen.


Benzo
Participant
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For headlights:

My cygolite has a nice solid + pulse (called SteadyPulse) mode where the light is mostly on, but then it pulses every few seconds to make you stand out a bit more (but it never stops lighting the path). I use that almost exclusively on the road at night.

During the day I tend to ride with a flasher.

Additionally, I’ve got a low power white light on my bag which I usually turn on to a slow flash.

In germany, many bike lights are designed with reflectors to direct light downard and forward, but not upward to avoid blinding drivers. However, they have some much more rigid and defined regulations for lights (which may seem weird and excessively restrictive compared to our minimally restrictive regulations).


mattjackets
Member
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The amount of ambient light makes all the difference. In a well lit city environment, biking on the street, I don’t think flashing/bright lights are much of a problem. However if it’s a dimly lit road or a trail, the light can significantly impair the vision oncoming vehicles…so they may swerve to miss something while they are closer to you.

On the trail though, I run a 600 lumen light and always shield oncoming riders/joggers from it with my hand. Just rest your fingers on the light and you can keep them in darkness while still lighting up your path. A bright steady light on the trail very effectively blinds other trail users…please NEVER use the strobe mode on a trail after dark!


Eric
Member
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I have two blinky white lights on the front and two blinky red on the back. On each side one on the helmet and one on the frame. I’ve never had anyone complain about it. Since I mainly ride on the roads in the dark I figure the more the merrier. I like having a white light on the helmet so I can point it at motorists poking out of a side street or pulling out of a driveway. It gets their attention.


stefb
Participant
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I have an 800 lumen cygolite and like benzo, I have it on the steady strobe, meaning it is on syeadily but pulses every few seconds. I am not even sure if that setting puts it at 800 lumens, but it definitely is bright. I think it catches the eye of the driver more than a steady light would. Most drivers just glance when they look both ways to pull out (if they do look), and this catches the eye. I also only mount on my helmet. On Ellsworth in particular, people have almost pulled out in front of me from a side street until I shine my light directly in their face. That keeps me safe. i feel like things are safer for me that way.

If you do any night mountain biking, then you have probably ridden with cyclists with head lamp mounts. I have gotten a few accidental bright lights to the eye, but I have never been unable to almost immediately ride again without trouble.

As for blinking lights and drivers: if they can’t see well enough because of blinking lights or anything else (bad weather, etc.), law says they shouldn’t proceed unless they can see clearly enough to drive, right?


ErinK
Participant
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I’ve definitely had problems as a driver when a cyclist nearby uses a bright flashing light – it can be painful, and it blows out my night vision in about a second. It also pulls my attention too much. I just want to keep looking at it. So I might be obsessed by the rider four lanes away heading toward me and missing an unlighted cyclist or black-clothed pedestrian in front of me.

(And yes, I do slow down in this situation and have occasionally stayed at a stop until the bike passed me.)

My other question is what it does for the cyclist’s vision – it can’t be helping you see the road, right? I’ve run with a single LED Knog on flash for visibility at dusk and it was pretty distracting for me when it got darker.

The one plus is that a flashing white is a clear sign of a cyclist headed your way, and that’s always nice to know. But I would much prefer if people used bright lights on solid (and aimed down a bit toward the pavement) with a smaller flasher.


dfiler
Member
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I think there is such a thing as too bright, both for biker safety and for the night vision of others. Or perhaps “too blinding” would be a better way to describe the issue.

My take is that a bright light designed to illuminate the road surface should not be set to flash after dark. However, cheaper dimmer lights designed to merely make a bicycle be seen, should always be set to flash.

Because I use a 1700 lumen helmet light, it is quite easy to blind drivers or other trail users. Riding single track in the woods it is pointed forward and used on the max setting. But when riding on double wide gravel trails or on the road, half power is sufficient. I also point it more downward when on the road so as to not blind oncoming traffic.

When stopped behind a vehicle at a red light, body position changes, aiming the light higher up and would blind the driver in front of me. For that reason I either look to the side, upward or partially cover the light with my hand. Not doing so blinds the driver via their side and rear view mirrors.

At times when riding on the road I will switch it to max. This seems appropriate when in an area with high ambient light. Or, if a car looks about to pull out of a parking spot, i’ll switch the light to max and shake my head so it pans over their car a couple times.


Benzo
Participant
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I wish the major US light manufactures (I’m talking about cygolite/niterider/planet bike/light in motion) at least gave the option for some sort of parabolic lens on the front to direct the light downward.

Is there a good DIY solution (or hack) to retrofit your lights to be less offensive to drivers, peds, or other cyclists?


StuInMcCandless
Participant
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Not mounting it super tight allows you not only to tip it down to keep it out of motorists’ eyes, but also allows you to adjust the tilt to account for variability in trail/pavement visibility.


Pierce
Participant
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A problem for me is that the light is so bright, I can adjust it at a wide variety of angles and it still illuminates the road pretty well, so it’s hard to tell from the saddle how far up it is in driver’s eyes


jonawebb
Participant
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You could just put tape over the top of the lens to create a cutoff above a certain height.


StuInMcCandless
Participant
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A hooded mirror would be preferable, if such a thing exists for bikes.

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