Govt to limit power of cycle lights ?

Vorpal
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Re: Govt to limit power of cycle lights ?

Postby Vorpal » 1 Apr 2013, 9:40am

If my light were easy to switch with gloved hands, similar to the one in my car, the switch would be quite big relative to the light; approximately the same diameter, and roughly 1/3 the length. So, overall 1/4 of the light (and probably 1/3 of the weight) would be switch. That would never satisfy the weight weenies! :wink:

Actually the push switch on the back of my light is not too bad. I can even manage it in ski mittens, though it sometimes takes a couple of tries.
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Re: Govt to limit power of cycle lights ?

Postby Geriatrix » 1 Apr 2013, 10:00am

Vorpal wrote:Actually the push switch on the back of my light is not too bad. I can even manage it in ski mittens, though it sometimes takes a couple of tries.


Some lights are OK, but even the ones like yours can be pushed out of adjustment when operating the switch, and the hand must still be moved off the bars. One solution would be to have a universal or standardised button conveniently located for each type of bar geometry which can operate lights from different manufacturers through standardised connectors. This would make switching between modes as easy as can be done on a motorcycle. The problem of bright lights exists both way's and I miss the ability to flash motorists who don't dim their lights (interpret flash any way you like :wink: ). Can't see that happening anytime soon though.
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sjs
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Re: Govt to limit power of cycle lights ?

Postby sjs » 1 Apr 2013, 10:18am

If any new regulations are enforced as rigorously as those relating to car lighting they will be of no practical significance at all, judging by the number of cars I see with one failed headlight.

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Re: Govt to limit power of cycle lights ?

Postby Geriatrix » 1 Apr 2013, 10:24am

sjs wrote:If any new regulations are enforced as rigorously as those relating to car lighting they will be of no practical significance at all, judging by the number of cars I see with one failed headlight.

I'm not so sure about that. There is a greater willingness to make a special case against cyclists. After all look at all the death and destruction we cause.
For a successful technology, reality must take precedence over public relations, for nature cannot be fooled - Richard Feynman

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Cunobelin
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Re: Govt to limit power of cycle lights ?

Postby Cunobelin » 1 Apr 2013, 10:39am

Geriatrix wrote:I wonder how much of the problem is due to poorly adjusted lights - LED's that are not sufficiently dipped, or lights that are on the wrong setting because it's difficult to toggle them to a more appropriate setting.

The switches on all the lights I have owned are poorly positioned, difficult to operate with gloved hands, and don't toggle conveniently between appropriate road modes, so a light mode will switch from bright to not so bright, to dim, to high frequency flashing, to low frequency flashing... Car lights are simpler, toggling between bright and dim with an easy to operate switch. How come manufacturers missed that concept with bicycle lights?


They didn't

Its simply that no-one wants lots of trailing wires on a bike.

Look at the popularity of the "all in one designs" - all of mine toggle through in order.

Some manufacturers offer thumb switches, but the uptake is very poor

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Re: Govt to limit power of cycle lights ?

Postby Philip Benstead » 1 Apr 2013, 11:50am

The brightness of 10 popular light-emitting diode (LED) bicycle lights was tested at a photometric laboratory
THE government has pledged to take action after a Sunday Times investigation found that 80% of popular bicycle lights are more powerful than the legal limit of brightness for dipped car headlights.

One of them exceeded the maximum for a dipped headlight by a factor of 13.

The brightness of 10 popular light-emitting diode (LED) bicycle lights was tested at a photometric laboratory. On their lowest setting and with angular adjustment to account for pointing down at the road, eight of the lights exceeded the legal maximum level for dipped car headlights. At their maximum brightness setting, nine of the lights were brighter than a car headlight.

The lights can also be set to flash, often at a brightness near maximum, giving an intrusive stroboscopic effect that could distract other road users and impair their ability to judge the cyclist’s distance or speed. At least 100 cyclists are killed on Britain’s roads each year.

Bicycle-light makers are engaged in an “arms race” to produce ever brighter lights. Stephen Young, managing director of Lumicycle, which makes the LED4Si light, said: “You have to offset the vulnerability of the cyclist and if that means causing dazzle to a driver, maybe that’s worth it.”

When pressed on whether the industry was out of control, Young conceded: “What you are saying is correct — I’ve heard it for years.”

Ben Terry, a student paramedic, claims to have sold 230,000 examples of the Cree XM-L T6 lamp from C&B Seen — the brightest light tested. Roger Terry, his father, who helps to run the business, said: “I’m not sure if we should be delighted that ours is the most powerful, or dismayed. We advise people to angle them onto the road and not ride on full beam.”

The Department for Transport (DfT) says current rules specify a maximum intensity of 70 candela — a measure of luminous intensity — but technology has overtaken that limit, which is now widely ignored.

When asked to clarify the maximum brightness allowed for a front-facing bicycle light, the DfT referred the inquiry to the Road Vehicles Lighting Regulations, which state that it is an offence for any light on a vehicle to “cause undue dazzle or discomfort to other persons using the road”.

When informed of the test results, Stephen Hammond, the road safety minister, said: “Cyclists are required to use lights to ensure that they are visible to others using the roads and to see the road ahead.

“However, we are aware that the law on vehicle lighting has not kept pace with developments in the market for bike lights, so we are reviewing the lighting regulations and hope to come forward with proposals to revise them later this year.”
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Re: Govt to limit power of cycle lights ?

Postby meic » 1 Apr 2013, 12:10pm

found that 80% of popular bicycle lights are more powerful than the legal limit of brightness for dipped car headlights.


Not only is that blatantly untrue, in an ideal world we would expect 100% of bike headlights to be more powerful* than dipped car headlights, just as we expect 100% of car headlights to be more powerful than dipped car headlights.

*What exactly does powerful mean? My car has 110W of "power" in its dipped headlights, how many cyclists can carry that amount of "power" for more than a few minutes burn time?.

I did say in an earlier thread that this would be sure to happen and it would be better if we jumped in first with an intelligent restriction on cycle lights before the authorities came along with a stupid one.
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Re: Govt to limit power of cycle lights ?

Postby gaz » 1 Apr 2013, 12:17pm

...The Department for Transport (DfT) says current rules specify a maximum intensity of 70 candela — a measure of luminous intensity — but technology has overtaken that limit, which is now widely ignored...


Perhaps we can legislate for the sun to be switched off in the day time, after all it exceeds the specified maximum intensity of 70 candela, and when cyclists die driver's claim that the sun dazzled them.

...The lights can also be set to flash, often at a brightness near maximum, giving an intrusive stroboscopic effect that could distract other road users and impair their ability to judge the cyclist’s distance or speed. At least 100 cyclists are killed on Britain’s roads each year...


I wonder how many of those deaths were at night?

This is nowhere near the pinnacle of journalism. It is very near the pinnacle of victim blaming.
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Re: Govt to limit power of cycle lights ?

Postby RickH » 1 Apr 2013, 2:39pm

I passed a cyclist with a very bright flashing front light while I was in the car approaching some red lights the other evening - one advantage of the bright flasher was that I was reminded of his presence because of the flashes lighting up the nearside mirror housing & door pillar even when I could no longer see him when he wasn't visible in either my mirror or rear window.

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Re: Govt to limit power of cycle lights ?

Postby CJ » 3 Apr 2013, 4:05pm

There is a problem. At CTC we have been getting an increasing number of complaints about dazzlingly bright cycle headlamps, from drivers, pedestrians and from other cyclists. When I get these lamps to review, I think it's great that they light up the world so well, but embarrassing when oncoming cars stop in their tracks at my approach! Yes this does happen, and no I don't think it's a good thing to blind the person steering an oncoming ton of metal!

Aiming the lamp downwards helps, but some of these lamps are so bright and so optically simple, that they have to be aimed down to only a few feet in front of the wheel before they cease to dazzle other road users. That makes the lamp useless to ride with. So what can you do? Some riders fasten the bracket a bit loose, so they can swivel their lamp down and up again, or shade the lamp with one hand, neither of which seem entirely satisfactory answers to the problem. Most lamps can be dimmed to a lower setting, but dimming and/or switching back to maximum, is invariably a whole lot more complicated, requiring several button-presses, than flipping the dip switch in a car. It's got to be that convenient, I think, before most people will do it.

Until recently I've only had the evidence of my eyes and the reactions of other road users. So when the Sunday Times asked if I was aware of the problem and offered to get some lights tested to see if there was any substance in the allegations that bike lamps are getting too bright, I had to agree.

Rest assured, the test was done properly. For your full information here's the technical basis of the tests conducted with my assistance, by Dr Gareth John, at the laboratory of Photometric & Optical Testing.

Glare is a subjective matter. It can be measured, but depends upon the brightness of the general scene and position within that scene of the source of glare, as well as its ‘luminance’. Luminance is the intensity of light emitted (in candela) in a particular direction, divided by the area it comes from.

According to the Road Vehicles Lighting Regulations, it is an offence for any light on any vehicle (that includes bicycles) to “cause undue dazzle or discomfort to other persons using the road”. So the law is subjective also. To put some numbers on how bright a light can be before it’s likely to dazzle, we must refer to design standards.

Motor vehicles must be ‘type approved’ before they can be used on the road and as part of that approval their lighting must conform with ECE regulations. These regulations ensure that headlamps do not dazzle other road users by putting a top limit on the intensity of light emitted above the horizontal (and to the offside) by a dipped headlamp. For technical reasons different types of lamp have different limits, but the most an oncoming road user should see from any ECE approved headlamp, when dipped, is 625 candela.

When it comes to bike lamps, the British Standard is out of date to the point of irrelevance. Headlamps are no longer made to BS (so I told the Sunday Times to forget about its over-cautious anti-dazzle limit of 70 candela, but unfortunately the DfT dragged that up :( ) and most of those on the market conform to no recognised standard. A few lamps on the UK market however, are made to conform with German traffic regulations, which limit the intensity of light emitted by a cycle headlamp, above the horizontal, to 200 candela. A lower limit than motor vehicles is justified by the smaller size and hence brighter appearance (i.e. luminance) of cycle lamps, and 200cd is a reasonable figure bearing that in mind. Since bike lamps cannot (usually) be dipped, this regulation (and our defunct BS) assumes that the lamp is aimed downwards at an angle of 3.4 degrees. An international (ISO) standard for cycle lamps is currently in preparation, which most countries will probably ignore - except Germany and France. This has the German anti-dazzle limit of 200cd and aims the lamp down at 3.5 degrees. Note: the lamp can be as bright as anything in the beam centre, neither BS nor German nor ISO standards put any limit on a bike headlamp's peak intensity, it's only above 3.5º up from that hotspot that there is any limitation.

Most cyclists will probably aim their lamps a little higher in order to see far enough ahead (I checked the headlamp on my commuter bike and it's aimed down at only 2 to 2.5º), but to be fair we measured at 3.5 degrees above the centre of the beam’s hot-spot. I recommended reserving our sternest criticism for lamps that could not easily be dimmed to 625cd, the same as a dipped car headlamp, even though car lamps are bigger and hence exhibit less glare at the same intensity. Most of the bike lamps we tested exceeded that nevertheless, and some by a huge amount!

Fortunately perhaps, it takes a lot more light to look a little brighter and to represent the way in which these differences are actually perceived I charted our measurements on a logarithmic scale. The red spots indicate the intensities of every lamp’s beam centre when it’s set for maximum brightness, green spots are the maximum values 3.5º above there, and green boxes mark the corresponding values on the lamp’s minimum setting.

Dazzle.GIF

I said we should be happy with a lamp that could be dimmed to less than 200cd, or even 652cd, in one simple movement and likewise back to maximum, just like dipping a car headlamp. But with most lamps it takes several button-presses to go from max to min, or back again.

We didn’t measure the flash modes, but some of these lamps appear to flash at maximum intensity. This might not be a problem in daylight, but even their minimum 3.5º intensities seem likely to cause discomfort if flashed at night.

So that's it. There is a problem and you'd better believe it. Sure the Sunday Times has exaggerated it a bit, like they do, but the manufacturers of cycle lamps seem to need a stronger incentive than we've so far been giving them, to get a bit cleverer in the optics department and/or provide us with simple dimming facilities, so we can use their products more responsibly.

There's one lamp in that line-up, the B&M Ixon IQ, that conforms with German regs and has a much more sophisticated optical design than any of the others, with a very sharp cut-off a couple of degrees above the beam centre. Admittedly its beam centre isn't as brilliant either, as any of the others in the test, but look at the difference: this lamp is more than 15 times brighter in the beam centre than 3.5º above. Combine this optical design with a more powerful LED and it would be possible to equal the performance of some of the brightest lights in test without exceeding 625cd at 3.5º up. Combine it with an easy dimmer switch to one-quarter power and it would pass the proposed ISO standard.

Another lamp in that test, the Supernova Airstream, has fairly clever optics and achieves a less abrupt cutoff. On lowest setting it just scrapes under 200cd at +3.5º, but it takes several button presses to get to/from that setting. This lamp also comes in a version that's legal in Germany, which I guess must be programmed to get there in one. But the UK importer sells the 'international' version. Pity.
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[XAP]Bob
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Re: Govt to limit power of cycle lights ?

Postby [XAP]Bob » 3 Apr 2013, 4:30pm

divided by the area it comes from


That seems a bit harsh - we are (mostly) using LEDs with an area of about 1mm squared - or it the frontal area of the lens?

Still a bit harsh - and can some-one test some of the audi DLRs? They're rather bright and small...
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Re: Govt to limit power of cycle lights ?

Postby kwackers » 3 Apr 2013, 4:56pm

[XAP]Bob wrote:or it the frontal area of the lens?

Doesn't matter the luminance stays the same whether measured at the chip or the lens.

Car DSLR's suffer from the same issues as bike lights. No cutoff and a bright pin source of light that throws forward.

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Re: Govt to limit power of cycle lights ?

Postby xpc316e » 3 Apr 2013, 5:00pm

The whole issue is academic as the Police will not have either the manpower, or will to enforce any possible law changes. Given that as far as I can see nobody gets pulled up for riding without lights, how many will be reported for an offence that requires a laboratory full of optical instruments and meters to prove such offence has been committed?

What is much more likely to happen is a change in British Standards to reflect the capabilities of the lights now on the market - now that would be a step in the right direction.
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Re: Govt to limit power of cycle lights ?

Postby TonyR » 3 Apr 2013, 5:03pm

CJ wrote:There is a problem. At CTC we have been getting an increasing number of complaints about dazzlingly bright cycle headlamps, from drivers, pedestrians and from other cyclists. When I get these lamps to review, I think it's great that they light up the world so well, but embarrassing when oncoming cars stop in their tracks at my approach! Yes this does happen, and no I don't think it's a good thing to blind the person steering an oncoming ton of metal!


Part of the problem is that cycle light manufacturers con uninformed purchasers by entering into a lumens war. Just look at the threads on lighting here and you find most people seduced by big lumen numbers. Lumens are an essentially useless measure but they win the lumens war by spraying light all over the place because any obscuration of the beam drops the lumens output. As you rightly say its the candela in the direction of the road ahead that matters, not the lumens, and some sort of candela based standard would be the answer if there weren't cheap high lumen Chinese imports and little likelihood of anybody ever enforcing the standards.

Another aspect of the problem is the 3.5º problem. Because lights have to be taken on and off bikes to avoid theft (dynamo lights excepted), even if you were careful, setting the lights when you put them back its unlikely you would be able to set them up to the necessary accuracy. And you just need to look at the number of people cycling around with their rear lights pointed at the ground, sky or sideways to realise the 3.5º measure is meaningless to most people.

Not sure what the solution is though. Do you have for comparison the candela limit of a full beam car headlight? That would seem to be a more suitable measure than a dipped headlight one as most cyclists frequently have to face full beam headlights from car drivers outside of towns.

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Re: Govt to limit power of cycle lights ?

Postby Tonyf33 » 3 Apr 2013, 5:28pm

Given we are now subjected to many unlit suburban roads across swathes of the country because councils are switching off lights after midnight I cannot see how 70 candela would even remotely be enough to see by nor even safe especially given the shocking state of the roads so that HAS to be changed sooner rather than later to a much more sensible figure. 652 would be fine as a starting point but as others have said what plod are going to bother to enforce it!

Additionally I'm certain that far many more people complain about car headlights being too bright and/or misaligned than cycle lights. If there is any addressing of a situation it is the motor vehicle headlight that should be looked at more intently(not too much or it'll burn your retina's...lol).
Additionally you can easily fit extra bright bulbs to cars that are openly sold on the market that aren't legal like 100watt bulbs (even Halfords sold them) and other 'approved'/legal lights that are 300% brighter than Halogens. I run std Halogens in my passat, 3 times brighter is ridiculous but you see it all the time.
Just because there might be a warning on the packet to say off road use only it doesn't stop drivers from fitting and blinding people. What about fog lights been used at night all the time, I had some muppet only Sunday up my trumpet with his Rally style lights blinding me via the rear view on an unlit road that is hard enough to drive as it is.
I'll be fitting what I deem is required to keep me safe and enable me to see the road ahead.