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How Bright Is Too Bright

This topic contains 96 replies, has 30 voices, and was last updated by  Mick 10 mos, 1 week.

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Vannevar

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Nov 6 2012 at 5:32pm #

Speaking of too-bright lights, if anybody’s looking I thought I’d mention the DesignShine project. I’ve been on the waiting list for quite a while and I just took delivery on the tail light, very pleased so far.


pearmask

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Nov 6 2012 at 6:31pm #

Man, how had I not looked at those B&M battery-powered lights? Want.


Ahlir

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Nov 8 2012 at 1:46am #

On a dark-ish trail (like Junction) I’ll use the non-blink light, pointed down to about 10m ahead of me. On streets it’s always on blink. (And the back is always on blink.)

My impression is that most riders on trails use steady lights. I like the fact that you can see people approaching from a good distance. It’s great. If you don’t have lights, draft someone who does (if you can).

Bikers with crappy (low-lumen) lights are dangerous. I find them hard to spot and have to pay more attention to be able to notice them. (So you can imagine what car drivers are dealing with.)

Bike lights (and car head-lights) are not blinding if you don’t look at them directly; just look at the ground that they’re illuminating, or to the side of the road. Works for me.


jonawebb

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Nov 8 2012 at 1:56pm #

Saw someone coming down Forbes near Dallas around 6:30 last night with a really bright light. As bright as a motorcycle or car headlight. Totally cool.


PghDragonMan

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Oct 8 2013 at 6:37am #

Sometimes you can have all the lighting in the world and it won’t help, especially if the other person is in HUA mode. See my blog for one such account:
Dragonman’s Bicycle Blog


PghDragonMan

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Oct 8 2013 at 6:46am #

Actually, this is a better link, it goes direct to the story:

Dragonman’s Bicycle Blog – Dangerous Distracted Riding


Vannevar

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Oct 8 2013 at 7:20am #

Awful story but a great blog, +1 !


edmonds59

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Oct 8 2013 at 10:20am #

Not meaning to be a crank, but it seems like the Weaver gave plenty of advance notice that she was an accident waiting to happen, and maybe it would have been prudent to slow to even less than 12 mph when passing. I observe people trying to maintain a “pace” on the trails and it does cause me to wonder. Sometimes as they say discretion is the better part of valor. Sorry to hear of your injuries, glad it wasn’t worse.
Also FWIW I am NO fan of earbuds when riding.


UnrealMachine

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Oct 8 2013 at 11:32am #

Back to the original question of how bright is too bright. Let’s first compare the lights on a bike to the other lights on the road. Traffic signal lights are over 1,000 lumens (some even 2,000). Brake lights are 350-500 lumens x 4. Headlights can be 1500+ lumens. Police sirens are designed to be seen from 2+ miles away. The lights that a typical cyclist rides with are an absolute JOKE in terms of brightness when compared to those above. That’s why they are often still unnoticed until they are 20 feet a motorist (sometimes that’s already too late). Consider the playing field you are competing against when you choose how bright of a light you really need.

When the police/fire/EMT’s want to be seen by other other motorists/cyclists/pedestrians, they use bright flashing lights. People simply respond out of instinct when they see flashing lights (even in the corner of their eyes). Motorists making a left turn might or might not notice a cyclist coming the other direction, but they are much more likely to notice flashing lights and the cyclist attached to them. Those flashing lights illuminate more than the profile of the bike and therefore offer an exponentially larger array of surfaces to project onto and be seen my motorists BEFORE they see your bike.

Lastly, I challenge anyone to find a single documented case of a driver/cyclist/ped that was in an accident caused by “blinding cycling lights”. Compare those to all of the cyclists that are hit by motorists who “never saw the cyclist”. Instead of hoping that another car notices your existence, increase the odds in your favor by having bright, blinking lights in the front and back of your bike. Slightly annoyed drivers vs getting blindsided by a motorist who isn’t paying attention. Your choice.


UnrealMachine

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Oct 8 2013 at 12:01pm #

Just one comment on dynamo lights. You are at a stop and your bike is producing zero light since there is no power source when at zero velocity. You emerge from the stop with either zero or extremely dim lighting. The cars around you and the ones approaching (from any direction) hit you since they don’t see you or your lights.

Yes, dynamo lights look good on paper. But in practice, they present multiple scenarios in which they can fail. Additionally, the amount of current they can generate might not be nearly enough to power all of the lights on the bike.


edmonds59

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Oct 8 2013 at 12:08pm #

High end dynamo lighting systems incorporate battery back-ups to resolve the standing stop problem. http://www.peterwhitecycles.com/b&m-hl.asp


Steven

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Oct 8 2013 at 12:10pm #

Dragonman, I’m afraid your post doesn’t belong in this “How Bright Is Too Bright” thread. It clearly concerns a dim bulb. :-)

Edmonds59, if the clueless cyclist was doing 10 mph, as stated, I’m not sure Dragonman could have gone much slower and still gotten past. I don’t know how to safely pass somebody who weaves across the entire trail and won’t respond to shouting. Was he supposed to just remain behind the clueless cyclist indefinitely? (I suppose clearing the tunnel and waiting for a rideable shoulder before trying to pass might have been safer in hindsight, but that could take a long time on some trails.)


jonawebb

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Oct 8 2013 at 12:11pm #

@UnrealMachine, dynamos these days work pretty well, I think mostly because LED technology has gotten so good. They’re useful to have on long rides and on daily commutes since you don’t have to worry about batteries. You just hop on your bike and go. But I would always combine them with helmet-mounted lights for the reasons you mention, and as a backup.
@Edmonds, I think you’re talking about standlights, powered by capacitors. I was never happy with the light output of them on fancy Supernova lights.


UnrealMachine

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Oct 8 2013 at 12:38pm #

@jonawebb

It depends on what the current draw requirements are for the individual light setup. My point was that some of the most critical lighting demands (instances where a cyclist needs to be visually detected by a motorist) are when a cyclist is moving at a slow speed or at a stop. The dynamo light will simply not be able to supply the necessary current and the lights will be dim or completely off when you need them the most.

While LEDs are constantly evolving, so to is battery technology. Lithium ion batteries are light and powerful. A 4×18650 setup can provide 5200+ mAh for $50 or less and weigh ~220 grams. Most lights are driven at well under 1A in flash mode so you can easily get 6-10 hours or run time. Often much more.


reddan

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Oct 8 2013 at 12:38pm #

Additionally, the amount of current they can generate might not be nearly enough to power all of the lights on the bike.

Out of curiosity (as I’ve used dynamos in addition to battery-powered lights for many years, and have had no problems), what dynamo were you using, and what lights were you trying to power? (Also, just FYI: dynamo hubs are mostly constant current, in the range of 300-500 milliamps. If you wire the lights in series, you don’t really have to worry about “not enough current to power all the lights”, barring a truly spectacular number of LED emitters.)

In my experience, battery systems generally beat dynamos on cost, portability, and (as mentioned above) remaining brightly-lit while stationary for long periods of time. Dynamos beat battery systems for convenience/usability (install, turn on headlight and tailight, and forget about it) and for use in cold weather (as every battery light I’ve used drops in output significantly as the temperature drops below freezing, but dynamo-driven lights are unaffected). Both have points of mechanical/electrical failure, of course.

I take the same tack as Jon; my dynamo drives the lights permanently affixed to my bike, and I have a decent set of battery-powered lights on my helmet as backup. If I really wanted to be spiffy, I’d invest in the dynamo lighting system which also charges AA batteries, so I could charge my helmet light batteries while riding.


UnrealMachine

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Oct 8 2013 at 1:13pm #

@reddan

I have not used a dynamo to power my lights. My helmet light alone is driven at 2.38A (MS 880 clone). I understand that the current is constant on a dynamo, but that only occurs once the bike attains a certain minimum velocity (do you happen to know what that is?).

It’s certainly possible to have the dynamo wired in series to a Li-Ion, but that would strain the battery with too many charge/discharge cycles. Way more economical to just charge the battery when needed (read: keep track of your ride time and recharge before battery goes dead).


jonawebb

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Oct 8 2013 at 1:25pm #

The minimum velocity is pretty low — a little faster than walking. But dynamos do produce less current than batteries. It would be really hard to beat a battery for current.
I think the choice of a lighting system depends on more than just light. Me, I would always be forgetting to recharge the batteries. I like the freedom of not having to worry about things with a dynamo. Your bike becomes something you can depend on anytime. The night is irrelevant.
I almost ran into a biker coming up the wrong way this morning (in the dark) on the Forbes bike lane, just after the cut through from Beechwood. No lights, no helmet, just riding along. People really do need to get some lights, especially now with days getting shorter. They are expensive, especially if you’ve spent $20 or nothing on your bike, but you really need them.


reddan

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Oct 8 2013 at 1:32pm #

I understand that the current is constant on a dynamo, but that only occurs once the bike attains a certain minimum velocity (do you happen to know what that is?).

I’ve not measured output while riding, so can speak only anecdotally.
On a Schmidt 28 or Shimano DH-3n7x hub, flickering stops and the light becomes steady at a slow walking pace of 2-3 mph…even while ‘enjoying’ extended late-night hill climbs at 4-6 mph, I get plenty of light.

That said, I have seen a classic dynamo system from the 70s in use (bottle dynamo mounted to frame with brush rubbing sidewall of tire, halogen lamp), and it was certainly not what I’d consider adequate. No standlight, no wired taillight, and no real light output until 10+ mph.

As far as charging goes, I prefer lights that I can either not worry about at all, or recharge by buying batteries at a convenience store at 4 AM. Because I A) suck at remembering to charge things and B) occasionally find myself riding extended distances overnight. Of course, I freely stipulate that my use patterns are not those of most cyclists…


edmonds59

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Oct 8 2013 at 2:24pm #

Steven wrote:Was he supposed to just remain behind the clueless cyclist indefinitely?

Whoa Nelly, that sounds suspiciously like the position some drivers take in the car/bike relationship, and we’re always going on about how they should wait until it’s safe to pass. I can easily ride as slow as 3 mph if need be. He didn’t mention that he was delivering a donor heart, so I assume stopping was an option, but maybe this is a subject for another thread.


byogman

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Oct 8 2013 at 2:40pm #

My question is more along the lines of, ok, cyclist ahead keeps drifting, keeps drifting, unresponsive to shouts why keep shouting?

Why not hit the breaks earlier and more gently and just make for the opposite side of the (apparently decently wide) trail so there’s room to pass someone totally oblivious safely? I think we all do that at some point or another around oblivious earbuds in walkers and joggers. But anyways, maybe the drift was faster than portrayed, and of course hindsight is 20/20.

Referring back to the thread title, too bright is hard to find. I have accidentally had my headlight aimed too high, however.


Steven

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Oct 8 2013 at 3:21pm #

@edmonds59: OK, that’s a fair point. So I guess the answer is yes. If you can’t pass a bike on a trail safely, you wait for as long as it takes, even if the bike you’re trying to pass is swerving randomly across the entire path. Maybe especially then.

@byogman: As I understand it, the clueless cyclist was swerving enough that there wasn’t a safe side. As I recall, the National Tunnel has ruts, dripping water, and it’s relatively dark so you have less time to react to them. That could have been responsible for a lot of the swerving. Maybe avoid passing in tunnels if you can help it?


reddan

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Oct 9 2013 at 6:00am #

Referring back to the thread title, too bright is hard to find. I have accidentally had my headlight aimed too high, however.

Me too…I’ve blinded a few pedestrians on Smithfield St Bridge that way.

Personally, I think the more important question is “how bright is bright enough?”


RustyRed

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Oct 9 2013 at 9:56am #

edmonds59 wrote:High end dynamo lighting systems incorporate battery back-ups to resolve the standing stop problem. http://www.peterwhitecycles.com/b&m-hl.asp

Thanks for this link, I actually found a fork mount light there that fits my needs! A handlebar headlamp is useless for illuminating the ground in front of me with a front basket.

I also love their sense of humor. I found this while poking around looking for a fork mount: http://www.peterwhitecycles.com/wmds.htm


Mick

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Oct 9 2013 at 9:58am #

reddan wrote:as every battery light I’ve used drops in output significantly as the temperature drops below freezing, but dynamo-driven lights are unaffected

As winter comes, this is reminder is timely.

I rid in all weather. Bad conditions+ inadequate light is not optimal.

Will look into being a dYnAmO!


edmonds59

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Oct 9 2013 at 10:26am #

Mick, just watch out for that dynamo hum.


Drewbacca

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Oct 9 2013 at 11:02am #

UnrealMachine wrote:

Yes, dynamo lights look good on paper. But in practice, they present multiple scenarios in which they can fail. Additionally, the amount of current they can generate might not be nearly enough to power all of the lights on the bike.

I keep an extra blinker on my dynamo powered bike for this reason, you adapt. At some point, I’d like to add a 300 lumen helmet light to my set up. I do agree that this is a weak spot for some dynamo setups, although my brake light stays on for a good ten minutes at close to full brightness even when my headlight goes out. I also keep a separate blinky on the back as a 1w LED tends to grab attention better.


Drewbacca

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Oct 9 2013 at 11:13am #

edmonds59 wrote:Not meaning to be a crank, but it seems like the Weaver gave plenty of advance notice that she was an accident waiting to happen, and maybe it would have been prudent to slow to even less than 12 mph when passing. I observe people trying to maintain a “pace” on the trails and it does cause me to wonder. Sometimes as they say discretion is the better part of valor. Sorry to hear of your injuries, glad it wasn’t worse.
Also FWIW I am NO fan of earbuds when riding.

I think you nailed it… and Dragonman admitted to all of these things in the blog, even if they were played down. The earbuds aren’t the biggest part of the problem with the other rider, the fact that Dragonman was behind her for a while and she was unaware of his presence in addition to the wearing of earbuds was the problem (but, we’ve already determined that she was a novice rider swerving around). I think it is important that Dman confronted her to make her aware of some things, but ultimately, the responsibility lands on the OP. You choose a bad place to pass, a place where you are not expected to pass, a place where it is more difficult for a novice to look over her shoulder and see you. There were a lot of things within your control. I can’t help but think how much worse this could have been if a ninja no-light cyclist came from the other direction.

I totally understand your anger and frustration, but take the earbuds out of the picture and it still could have played out the same way for various reasons. I am sorry that you had to experience this, that sucks, and I appreciate the blog and your taking the time to share the experience.

*edit to add* you have a real knack for writing!


Mikhail

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Oct 9 2013 at 12:41pm #

Drewbacca wrote:You choose a bad place to pass, a place where you are not expected to pass

Why? I rode this part of trail quite few times and can tell that people pass other people both on two wheels and on “two legs” in this tunnel.


Drewbacca

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Oct 9 2013 at 1:14pm #

Mikhail wrote:
Why? I rode this part of trail quite few times and can tell that people pass other people both on two wheels and on “two legs” in this tunnel.

Maybe it’s just me, but I try not to pass in confined areas like over bridges and in tunnels… I wouldn’t expect someone to overtake me in such a location (but then, I’d be aware of their presence and give them a chance to pass before reaching it in the first place… or I’d speed up until I got through it).


UnrealMachine

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Oct 10 2013 at 11:27am #

Discussion split from: http://bikepgh.org/mb/topic/hit-by-a-car/#post-284338

rice rocket wrote:7 is right around dusk at this time of year, probably the absolute worst time of day for visibility, even more than when it’s fully dark. Lights barely show up, and even flouro colors are barely visible. I very much avoid riding around then.

This is very true as evidenced by the fact that a steady beam of light does not greatly enhance a cyclist’s own visibility of the road during these conditions. There is not enough contrast for this light to stand out to a passing motorist as well. A light that is flashing is perceived quite differently during dawn/dusk though. That is to say, the background reference light is now in a dynamic state with the frequency of the flash. Additionally, the light reflected off of smaller surfaces such as street signs, other vehicles, etc. will be more visible to motorists. Motorists are programmed to respond out of seeing flashing lights (police cars, etc.) and flashing lights are considerably more visible than steady lights at dawn/dusk. The best demonstration of this is to simply keep an eye out for cyclists who are using a flash mode during those time periods and compare their visibility to others using a steady beam.


UnrealMachine

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Oct 10 2013 at 11:41am #

Discussion split from: http://bikepgh.org/mb/topic/hit-by-a-car/

jonawebb wrote:@unrealMachine, I take back what I said about the light not being an issue — a 1/2 watt LED light with a weak battery is pushing it…

But how many cyclists are using a 1/2 watt LED or worse? I would guess that 20-25% of cyclists I see use zero lights at all. Of the remaining 75-80%, I would say that 75% of those riders equip themselves with a setup similar or worse to that 1/2 LED light. At best, less than 20% of riders have what I would consider the minimally acceptable lighting setup in terms of enhancing the visibility of the rider to motorists. Personally, I would put the number at closer to only 5-10%.

Certainly the cost of lighting in relation to the bike is a great consideration, but the lighting on the bike can be just as or even more valuable to a cyclist in terms of avoiding a potential accident. Since there is no standardization for lighting, people wrongfully assume that a $10 light is going to enhance their visibility and justify that assumption by standing in front of the light and looking directly at it. Certainly all lights look bright with that approach, but real world cycling conditions expose a rider to all kinds of different distances and angles from a motorist. That’s where most lights fail because in real world applications, their visibility is actually quite limited. If a motorist can only see your light from 30 feet away and staring directly into the light, it leads itself into many scenarios in which there is not enough time/space for either party to react.


byogman

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Oct 10 2013 at 12:10pm #

Just out of curiousity, how do you judge what is minimally acceptable measures for visibility?

I’ll start with my “system”, which was really more of an accumulation of things that seemed like good ideas at the time than anything planned.

I have a 1 watt rear blinker, and a pathetic blinker in front that looks like it belongs on a keychain as the lights most frequently running. Both are helmet mounted. I have a strong (900 lumen) headlight bike mounted that I use perhaps less than I should, usually only about when streetlamps come on. I use it in steady state, not blinking mode.

Side visibility used to be my weak point, but I don’t think it is anymore since I plastered on retroreflective tape to the visible part of the frame (panniers block the rear) and fork.

Also added the tape to the visible part of the rear fender to supplement the reflector and added strips to the sides of my helmet.

I tend not to wear the hi-viz clothing, just whatever I’d be wearing normally except when I know I’ll be changing (and I probably push the stink boundaries a little further than I ought).


jonawebb

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Oct 10 2013 at 12:12pm #

One of the reasons I use helmet-mounted lights is that, in addition to flashing, they move around in an anthropic kind of way. That’s got to help arouse a driver’s empathy.
Also, they’re high up, so drivers can see them farther off. So even if they only look up occasionally from their texting, they’ve still got a chance to see me.
And when I’m approaching an intersection, I can aim the headlight so it shines directly in the driver’s eyes, increasing the chance they’ll pay attention.
Basically, you have to think of them as dull monkeys who have the ability to turn the wheel and press the brake and accelerator, but no higher brain functions, and do whatever you can to draw their notice.


helen s

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Oct 10 2013 at 12:29pm #

“Basically, you have to think of them as dull monkeys who have the ability to turn the wheel and press the brake and accelerator, but no higher brain functions, and do whatever you can to draw their notice.”

as long as you do not piss them off too much in the process….

I often use a similar thought process for riding in traffic.


Drewbacca

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Oct 10 2013 at 12:45pm #

helen s wrote:
as long as you do not piss them off too much in the process….

Yes, I believe that eye-contact is more advisable than light-in-eye-contact, when possible… I guess it depends on distance.


jonawebb

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Oct 10 2013 at 3:40pm #

It’s really hard to see eyes for eye contact in the dark.
My helmet headlight (which is non-flashing, BTW) is the PrincetonTec Remix. It has variable brightness and when I don’t need the extra brightness I doubt it will stimulate aggressive behavior in the monkey brain. If I was running it turned all the way up I’d briefly flash drivers with the light instead of just staring at them as I approach.


UnrealMachine

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Oct 10 2013 at 4:30pm #

byogman,

That’s a good question. Honestly, I’d have to defer to the “I know it when I see it” answer since, as I stated, there is no standardization for bike lights here. I would base my assessment on a light setup with how it performs in terms visibility at a distance, how much square footage the light can illuminate and how it performs at close distances & sharp angles. Since you admit that your front blinker is weak and that you only use your other front light at your discretion, I would say that you are not even using your setup at its full potential. In low-lighting scenarios (~dawn/dusk) where you might be hesitant to turn on your better front light, your reliance on reflectors is completely dependent upon other sources of light (streets, vehicle, sun, etc.). Those conditions change frequently (shadows, etc.), so your setup lacks consistency as well in my opinion. Overall though I’d say you are still better off than 80-90% of the lighting setups I see. What prevents you from using your 900 lumen light as a flashing unit on a regular basis?


Mick

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Oct 16 2013 at 1:50pm #

A thought: if your light is harder on the eyes than the low beam headlight on a new car, that’s too much, IMO. That isn’t uncommon.

Probably more obnoxious by being smaller area light source, pointing at people’s eyes, and blinking than actual brightness.


byogman

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Oct 16 2013 at 7:46pm #

What prevents you from using your 900 lumen light as a flashing unit on a regular basis?

Just laziness and frankly a dislike for strong flashing lights. For the rear blinker there’s the justification that people continuously need to be aware. In front it’s really only helpful in route crossing/joining scenarios. But I suppose those are probably frequent enough that I just ought to do it anyway.


salty

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Oct 16 2013 at 8:09pm #

fwiw, a solid white light is legally required. you can augment it with a flashing light but not replace it.

http://www.legis.state.pa.us/cfdocs/legis/LI/consCheck.cfm?txtType=HTM&ttl=75&div=0&chpt=35&sctn=7&subsctn=0

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