"Flashlight Etiquette" for Cyclists

[Bandgap]

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.

Wow

Bandgap Steve - who didn't really contribute much with that comment, but was amazed.

 

[Tsportmat]

I use a Fenix TK12 for commuting. It's fine for mostly lit streets and being seen. Although some of the spill may get to drivers' eyes, I don't think it dazzles. Certainly not more than a car headlight. I also run an eBay XML-U2 light when I'm going off road where I need more light, but while returning home on the road I was flashed a couple of times. I don't use that one so much now (except off road) as I think the spill is a bit too bright (perhaps I just had the angle wrong that day).

However, I do think cyclists having too bright lights gets noticed more than cars, perhaps because they're more white or from a smaller source, but if you star into any light (car or bike) you're going to get 'sunspots'.

Either way, I've been toying with the idea of getting a Fenix BT20, looks a great all around light and couple be used with a helmet light off road. The only thing stopping me at the moment is the price.

 

[mcnair55]

I live in a rural area and a cycle path runs along this section where i live as it is the main road to the local hospital and many of there staff cycle to and from work.I have noticed over the last couple of years the rapid increase in brightness in riders lights and after looking in cycle shops i can see why,purpose built light for cycles can be hundreds of £,s.

These ignorant riders are blinding me on approach and should drop the light onto a dipped position,it will not be long before an irate motorist drags one of these id yachts off his cycle and aids his journey to hospital quicker than by cycle.

 

[Flamingtaco]

For the US, we need a beam & cutoff-like the StVZO spec but better, not just a flashlight firing forward and slightly downward. Something reflex based so you don't get the point source glare from the LED, like Philips SafeRide, and the like.

Blinking/flashing lights are for stationary objects. They never belong on the front, and should only be used on the rear if you are fixing a flat, etc.

For the first comment I totally agree, but the issue with that spec is that implementation to date works by blocking light. Whether a traditional reflector lamp (steal blocking cage around the sides and part of the front of the bulb) or a projector lamp (steal blocking flange in front of the bulb), as much as half of the total output of the light is lost.

For this issue alone, and also due to the nature of cycling needs, about the best we could do is to have some type of mechanism to block light from driver's eyes that can be disabled on the fly, so we aren't getting whacked with low hanging tree lims or bushes when we turn off onto a local trail, but blocking 50% of the light is going to have a HUGE impact on battery longevity when we try to compensate for reduced light with more LED's. As far as beam aim, good luck, so many cheap mounts out there that constantly slip... I always put my bar lights on the left side so I can aim them slightly away from oncoming traffic, but again, the lights are not spec'd for DOT use, the rules in place offer no guidance.

For the second comment, is there a ruling somewhere thay says blinking/flashing lights are for stationary objects, because if so, the police, fire department, works vehicles, and any driver trying to limp to the nearest garage is in violation.

While some states specify that cyclists on the road are to use a SOLID red read lamp, not all specify that it remain solid. I wouldn't want people dropping their red blinkies for a red DOT reflector as those suck if not aimed perfectly. but I do suggest they run TWO rear lamps, one solid (brightest), one blinkie, because having a solid lamp provides better depth perception and tracking, and by golly, we also need blinkies to get their attention in the first place unless running a very high power rear lamp setup.

 

[swhs]

For the first comment I totally agree, but the issue with that spec is that implementation to date works by blocking light. Whether a traditional reflector lamp (steal blocking cage around the sides and part of the front of the bulb) or a projector lamp (steal blocking flange in front of the bulb), as much as half of the total output of the light is lost.

Uhm, what? Half the light is lost? In which lamps? Certainly not StVZO compliant lamps with a reflector, no light is lost there.

For this issue alone, and also due to the nature of cycling needs, about the best we could do is to have some type of mechanism to block light from driver's eyes that can be disabled on the fly, so we aren't getting whacked with low hanging tree lims or bushes when we turn off onto a local trail, but blocking 50% of the light is going to have a HUGE impact on battery longevity when we try to compensate for reduced light with more LED's. As far as beam aim, good luck, so many cheap mounts out there that constantly slip... I always put my bar lights on the left side so I can aim them slightly away from oncoming traffic, but again, the lights are not spec'd for DOT use, the rules in place offer no guidance.

For the second comment, is there a ruling somewhere thay says blinking/flashing lights are for stationary objects, because if so, the police, fire department, works vehicles, and any driver trying to limp to the nearest garage is in violation.

While some states specify that cyclists on the road are to use a SOLID red read lamp, not all specify that it remain solid. I wouldn't want people dropping their red blinkies for a red DOT reflector as those suck if not aimed perfectly.

What is a red DOT reflector? In any event, any proper taillamp has a reflector that is in fact a retro-reflector, so aim is of not much importance.

but I do suggest they run TWO rear lamps, one solid (brightest), one blinkie, because having a solid lamp provides better depth perception and tracking, and by golly, we also need blinkies to get their attention in the first place unless running a very high power rear lamp setup.

 

[Flamingtaco]

Uhm, what? Half the light is lost? In which lamps? Certainly not StVZO compliant lamps with a reflector, no light is lost there.

StVZO doesn't apply in the US, so our standards are not quite the same, however, it is very expensive to design and build a light that successfully utilizes all light from the source and does not overwhelm opposing traffic, so nearly all automotive headlamps use various methods to absorb light that would otherwise travel in nefarious directions.

Low-beam reflector headlamps have to block all light exiting the lens directly from the bulb as this is too bright a source. Many also block some of the light exiting the sides of the bulb due to space or design constraints that limit the efficiency of the setup, resulting in stray light that must be controlled.

The 9007 bulb, seen in the first image, comes with an absorbing coating.

Popular in the 90's and 00's, many vehicles fitted with this bulb also had a blocking insert in the headlamp housing, seen in this image:

These inserts are not reflective on the bulb side, it would require too much definition on the insert to be cost effective. Prior to the use of higher resolution reflectors in the late 90's that permitted the disused of fluted lenses, most of the inserts were black oxide stamped steel brackets.

In this image we can see the shield in a projector lamp that makes it a low beam:

and the resulting cutoff, with an area circled that approximately indicates the focus of the lamp, to give an idea of the light that has been lost:

As probably one of the worst examples ever, my 95 Taurus used the 9007 bulb, which was rated at 1000lm +-15%. That meant a bulb could be as low as 850lm. The headlamps got so bad as they began to haze and the reflector began to lose reflectivity that Taurus owners must have accounted for a quarter of all hella projector module sales. I remember the first project to modify the halogen modules for HID bulbs. Fun days.

IIRC, a brand new housing was measured with a run of the mill bulb at 480 lumens OTT. BOTH headlamps put out less light total than the DOT spec rating for one bulb. Those were pathetic days.

Things have improved a lot, H9's produce more lumens (1250 nom, IIRC), and projector lamps are seeing higher implementation (although not always well executed), but the issue remains with bicycling to produce a system that is compatible with being on the road and providing enough light to be safe. I think the best option for the time being is to physically block emitted light once OTT, as getting mfg's to even consider complying with DOT (NHTSA) rules is a very long shot due to the costs involved. Yes, Phillips has done somethig, but they are a HUGE international company involved in ALL aspects of lighting and they own the automotive lighting realm. A golden savior might come in the form of optics designed for automotive use, but not the kind found in the LED aux lamps being sold everywhere now, but in access to optics produced for oem headlamp use.

What is a red DOT reflector? In any event, any proper taillamp has a reflector that is in fact a retro-reflector, so aim is of not much importance.

This:

The off-axis drop-off is so tight, the passenger headlamp in a car will not provide a reflection for the driver. If the driver's headlamp is out, or poorly aimed, or if the reflector is poorly aimed (cheap mounts, and who ever bothers to square the damn thing by anything but sight?), you get zilch.

3M's conspicuity tape is worlds better, but reflective devices are only add-ons, we really need to use effective lights. No amount of high quality reflective device is going to provide visilbility to the guy in the mid 80's mercedes with one busted bulp and the other pointing 30º to the left and down, running off a corroded circuit that only supplies 6V to it. Or the guy in the jacked truck that only runs his fog lamps because for some reason it's the thing to not use your headlamps in a non-road legal jacked truck.

 

[lectraplayer]

I too think cyclists could do a lot to improve safety, for them and me. It seems they don't know how to light their bikes. I say they need at least a solid light on both front and rear, optionally a blinkie or two, and definitely a separately switched headlight, not more than 30 watts halogen or equivalent, wide, well controlled beam. Bikes also need lots of retro-reflective surface area. ...or at least that is what I found works best on my bike.

 

[mcnair55]

I too think cyclists could do a lot to improve safety, for them and me. It seems they don't know how to light their bikes. I say they need at least a solid light on both front and rear, optionally a blinkie or two, and definitely a separately switched headlight, not more than 30 watts halogen or equivalent, wide, well controlled beam. Bikes also need lots of retro-reflective surface area. ...or at least that is what I found works best on my bike.

Our local police are not keen on the blinkie type rear lights as they stopped my son years ago and told him they were not allowed,load of rubbish i think but who am i to say without checking regulations,as a car driver i feel better seeing the rear of a cyclist with a flashing light.

 

[Steve K]

StVZO doesn't apply in the US, so our standards are not quite the same, however, it is very expensive to design and build a light that successfully utilizes all light from the source and does not overwhelm opposing traffic, so nearly all automotive headlamps use various methods to absorb light that would otherwise travel in nefarious directions.

.. and this is where you lost me. Are you talking about bicycle lights or car lights?

 

[kpangy]

In the UK I'm 99% certain I read cycle lights by law must be solid and not blink but pretty much every bike rider I've seen use blinkies, which when I'm driving find hugely annoying (blinky at the back not too bad as they are not overly bright).

 

[lectraplayer]

Nothing wrong with a blinkie, but when you have nothing but, it does nothing but confuse drivers. Having mostly solid lights gives drivers something to recognize.

For forward lighting, fast riders will not outrun the capabilities of a 30 watt Par36, and an 18 watt works fine for me. Cyclists only have so much battery capacity and so shouldn't waste power on excessive lumens, even when those lumens are efficiently acquired. I am also bad to kill the headlight while in city traffic as I can still see fine without wasting another 20 watt/hours of battery and still remain easily seen.

 

[MichaelW]

That was a 9004 not 9007. Same difference-one is transverse, on axial; both have the 'blacktop' coating applied.
Plenty of dual beam headlights did not utilize a 'blocking insert', as it was redundant-so long as you didn't remove the blacktop.
They were more for aesthetics, as seen in what looks to be a Ford Explorer headlight.
The back side of a projector cutoff shield is not 100% absorptive.

 

[swhs]

StVZO doesn't apply in the US, so our standards are not quite the same, however, it is very expensive to design and build a light that successfully utilizes all light from the source and does not overwhelm opposing traffic, so nearly all automotive headlamps use various methods to absorb light that would otherwise travel in nefarious directions.

Low-beam reflector headlamps have to block all light exiting the lens directly from the bulb as this is too bright a source. Many also block some of the light exiting the sides of the bulb due to space or design constraints that limit the efficiency of the setup, resulting in stray light that must be controlled.

The 9007 bulb, seen in the first image, comes with an absorbing coating.


Popular in the 90's and 00's, many vehicles fitted with this bulb also had a blocking insert in the headlamp housing, seen in this image:


These inserts are not reflective on the bulb side, it would require too much definition on the insert to be cost effective. Prior to the use of higher resolution reflectors in the late 90's that permitted the disused of fluted lenses, most of the inserts were black oxide stamped steel brackets.

In this image we can see the shield in a projector lamp that makes it a low beam:

and the resulting cutoff, with an area circled that approximately indicates the focus of the lamp, to give an idea of the light that has been lost:

As probably one of the worst examples ever, my 95 Taurus used the 9007 bulb, which was rated at 1000lm +-15%. That meant a bulb could be as low as 850lm. The headlamps got so bad as they began to haze and the reflector began to lose reflectivity that Taurus owners must have accounted for a quarter of all hella projector module sales. I remember the first project to modify the halogen modules for HID bulbs. Fun days.

IIRC, a brand new housing was measured with a run of the mill bulb at 480 lumens OTT. BOTH headlamps put out less light total than the DOT spec rating for one bulb. Those were pathetic days.

Ah, I see, you meant car headlamps. I suppose power was never an issue there and then you get the problem of "plenty to work with, no need to be careful about what we waste". Human nature

But at first I didn't understand as I thought you meant bicycle headlamps and these never use such methods of absorption.

Things have improved a lot, H9's produce more lumens (1250 nom, IIRC), and projector lamps are seeing higher implementation (although not always well executed), but the issue remains with bicycling to produce a system that is compatible with being on the road and providing enough light to be safe. I think the best option for the time being is to physically block emitted light once OTT, as getting mfg's to even consider complying with DOT (NHTSA) rules is a very long shot due to the costs involved. Yes, Phillips has done somethig, but they are a HUGE international company involved in ALL aspects of lighting and they own the automotive lighting realm. A golden savior might come in the form of optics designed for automotive use, but not the kind found in the LED aux lamps being sold everywhere now, but in access to optics produced for oem headlamp use.

Do you mean there is no competition to Philips in automotive headlamp optics with cutoff? Hmm. If so then this gives me an idea but more on that another time.

How is it with motorcycles in the USA? I don't see many in NL but the ones I've seen here have crap light distribution.

This:

The off-axis drop-off is so tight, the passenger headlamp in a car will not provide a reflection for the driver. If the driver's headlamp is out, or poorly aimed, or if the reflector is poorly aimed (cheap mounts, and who ever bothers to square the damn thing by anything but sight?), you get zilch.

Actually, there is an issue, but first this: It seems to be a retro-reflector so should throw the light back into the same direction that the light came from. However, the problem is perhaps that the reflection is perhaps too much into that specific direction, so not diffuse enough, especially for shorter distances (because of the difference of head height and headlamp height and a retro reflector is supposed to return the light in the same direction as it came from). I had been thinking about this issue for a while and I noticed how poorly red reflectors in taillamps on bicycles often are noticeable, even if my headlamp is aimed high enough to hit it. But perhaps this is just apparant because often they are pretty high and simply not enough light hits the reflector. What I often have btw. is that a taillamp at close range can be annoying by reflecting off of the plastic layer (which gives a whitish reflection), and logically the retro-reflection is not seen. This is due to the angle (headlamp lower than my head, large difference in angle). Anyway, I was thinking about the same as what you mentioned below, that a more diffuse reflector might be desirable and I was also thinking of this reflecting tape... Perhaps a reflector should be a mix of such tight and very diffuse reflection.

In contrast reflectors on pedals always work very well, very noticeable. A low placed retro reflector as mandated by StVZO (on bicycles) would make a more diffuse reflector unneeded. Here in NL I don't see many fender mounted (=low) taillamps or reflectors, so I need to do some tests...

3M's conspicuity tape is worlds better, but reflective devices are only add-ons, we really need to use effective lights. No amount of high quality reflective device is going to provide visilbility to the guy in the mid 80's mercedes with one busted bulp and the other pointing 30º to the left and down, running off a corroded circuit that only supplies 6V to it. Or the guy in the jacked truck that only runs his fog lamps because for some reason it's the thing to not use your headlamps in a non-road legal jacked truck.

 

[Flamingtaco]

.. and this is where you lost me. Are you talking about bicycle lights or car lights?

Automotive.

 

[Flamingtaco]

Do you mean there is no competition to Philips in automotive headlamp optics with cutoff?

No, just that they have a higher level of resources available to throw into LED reflector design.

How is it with motorcycles in the USA??

Haven't really delved into that. If I currently had a motorcycle, it would be fitted with Hella's 90mm projector lamps.

Actually, there is an issue, but first this: It seems to be a retro-reflector so should throw the light back into the same direction that the light came from. However, the problem is perhaps that the reflection is perhaps too much into that specific direction, so not diffuse enough, especially for shorter distances

There are four issues with DOT *mandated* reflectors for bicycles, which must be of the prismatic type.

1) The prisms are made of plastic that does not have a reflective backing. Some light passing through the reflector and is absorbed by the (typically) black plastic that it is attached to.

2) Reflectivity drops off quickly off-angle, as shown in this image:

3) They reflect very close to 0º, which causes problems when you are significantly off-angle from the light source. SUV's and trucks put you well off angle, as does having a mis-aimed driver headlamp.

4) The required rear reflector is red, absorbing a good bit of the spectrum of the source light. This is especially problematic with LED light sources (coming to a car near you!) as they may produce so little light in the red spectrum as to not reflect any useable light at all. I've noticed I cannot see the red part of the conspicuity stickers on the trailers at work with my bike lights.

The yellow reflectors are a lot brighter than the red ones, but again, off angle presents issues. They are useless, for example, when a cyclist has just cleared an intersection, and a driver is turning in behind the cyclist from the cyclist's left, especially when taking the left lane on a four lane road.

Anyway, I was thinking about the same as what you mentioned below, that a more diffuse reflector might be desirable and I was also thinking of this reflecting tape... Perhaps a reflector should be a mix of such tight and very diffuse reflection.

Now that diffuse reflectors are extremely efficient (consicuity tape, scotchlite fabric)... yes. I don't expect to ever see those two combined into one package in my lifetime, though. The DOT's given lip service on the bad headlamp specs for three decades, bikes aren't even on their RADAR.

 

[Steve K]

Automotive.

okay. Can we stay on topic?

 

[Marcturus]

{automotive}

okay. Can we stay on topic?

Flamingtaco, feel free to take your ideas to the general transportation lighting forum if you think you want to cover automotive as well as non-automotive. This bicycling section here tends not to get excited about lumen-killing projection lamps or dubiously reliable retroreflective devices.

 

[swhs]

{automotive}


Flamingtaco, feel free to take your ideas to the general transportation lighting forum if you think you want to cover automotive as well as non-automotive. This bicycling section here tends not to get excited about lumen-killing projection lamps or dubiously reliable retroreflective devices.

No, he is right about the reflectors. It's the same issue I noticed. The further away you are from a retro-reflector, the better it works and so the 0 degree angle he mentions is what I mean with that the light is returned to the same place as it came from, which is done with prisms.

But with that comes a problem of not being visible if my eyes are not at the same position (height) as the headlamp...

A true reflector is in general not desired because then the angle of how it's mounted matters in whether you see a reflection, but with retroreflectors the range of angles is very narrow. Note that the mount of the retroreflector thus does NOT matter (or it should not matter), so its effectiveness does not depend on some people badly positioning/angling them, but simply the reason that you don't see much of them in lots of cases is that they don't work except to reflect to a specific spot (or rather a quite tight range of angles). If your eyes are not in that spot, you won't see them... The best place to see a retroreflector is the place from which the light comes, which is the headlamp...

This means a retroreflecto has a range that is too narrow in some cases. Rack mounted taillamps for one are such a case which were very clear to me (pedal reflectors work well because you tend to look at those and thus spot a bicycle from a larger distance), and for very close range all of them are not that good because then you always run into the fact that your eyes are so far away (in angle to the retro-reflector) from the headlamp, that you don't see it except via e.g. normal reflection as I mentioned.

I don't see why a retroreflector can't be 'assisted' by other diffuse reflectors even if it's not in the rules, I think this is a good idea for a future taillamp and reflectors...

 

[swhs]

On Philips:

No, just that they have a higher level of resources available to throw into LED reflector design.

Yes, that's what I meant... More on this soon.

There are four issues with DOT *mandated* reflectors for bicycles, which must be of the prismatic type.

1) The prisms are made of plastic that does not have a reflective backing. Some light passing through the reflector and is absorbed by the (typically) black plastic that it is attached to.

I don't know how much this effects the actual reflected light, but I could test to see what difference it makes by putting say aluminium foil behind one. I've put it on my "experiments-to-do" list

2) Reflectivity drops off quickly off-angle, as shown in this image:

That's how retro-reflectors are supposed to work but I agree that there are issues with it. But they were initially made/designed to make sure lights get back to the sender no matter what orientation the reflector (mounted not perfectly vertical, or from hills so at an angle, height difference from hills too, etc.)

3) They reflect very close to 0º, which causes problems when you are significantly off-angle from the light source. SUV's and trucks put you well off angle, as does having a mis-aimed driver headlamp.

Mis-aimed headlamps will only matter in case they miss the reflector entirely.

4) The required rear reflector is red, absorbing a good bit of the spectrum of the source light. This is especially problematic with LED light sources (coming to a car near you!) as they may produce so little light in the red spectrum as to not reflect any useable light at all. I've noticed I cannot see the red part of the conspicuity stickers on the trailers at work with my bike lights.

Good point about why cool white is not desired, but as as far as I experienced it's not a problem in being visible if the reflectors are good. That is to say, with just about any cool white LED headlamp on my bicycle (and I've tested loads of types) the retro reflecting signs on the left hand side of roads here in NL are very well visible. And with the Philips Saferide 80 as I mentioned here long ago I even felt these signs we too good, or alternative explanation, the Saferide 80 emitted so much light in those spots, that it became annoying.

Perhaps there are different types/qualities of red retroreflecting material and it could be that you encountered those that don't work well enough, so that's why you noticed this with cool white lamps?

The yellow reflectors are a lot brighter than the red ones, but again, off angle presents issues. They are useless, for example, when a cyclist has just cleared an intersection, and a driver is turning in behind the cyclist from the cyclist's left, especially when taking the left lane on a four lane road.

Yep.

Now that diffuse reflectors are extremely efficient (consicuity tape, scotchlite fabric)... yes. I don't expect to ever see those two combined into one package in my lifetime, though. The DOT's given lip service on the bad headlamp specs for three decades, bikes aren't even on their RADAR.

Well, your ideas are similar to mine and I'm going to write on my website (http://swhs.home.xs4all.nl/fiets/tests/verlichting/index_en.html) that taillamps/reflectors should get a combined retro-reflecting/diffuse reflecting reflector, perhaps middle=retro, and on the left/right of it diffuse.

 

[Marcturus]

Sure, no doubt about the angular characteristics and the red color, everyone should keep those in mind when thinking about relying on retro-reflectors to get seen. In addition, low-mounted reflectors tend to get covered with snow, my pedal-mounted reflectors often come home sprayed in mud, and rack-mounted reflectors, even if they stay clean, tend to be situated above the automotive passing beams' cut-off at a distance if the road is even slightly bent the "wrong" way. IMHO, thinking how to look similar to a well-lit motorized vehicle seems a better idea than overestimating the effects of choosing wider retroreflexivity characteristics and skimping on active, visibly large area lighting.

@swhs: any inside scoops on Philips pulling out of pedal-cycle lighting?