|email | Bicycle lighting standard WHS-2015|
Bicycle lighting standards that I've read are poorly devised, don't include explanations of why the rules are a certain way, and they are not free. They are a sort of tax on businesses who need to abide by the rules for products (otherwise they may not sell their products!). These rules are either already paid for by government in which case this is just a tax to keep people in some publishing business at work doing useless administrative work, or made up by some organisation which wants to profit off of them. I have devised this standard as an example of how things should be done.
Further, standards and regulations (and import tariffs on all sorts of products) are used in trade negotiations and/or to keep competition out. Countries trade the rules (in regulations and which products to have import duties on and how much), for something else they want to get... The theory of one of the readers of my website on bicycle lighting, that the 70 cd above the horizon rule in BS-6102-3 was set to avoid German competition (who design for the German limit of 200 cd), could be true. So rules in standards are used like a weapon... Imagine if the BS6102-3 elaborated for all rules, why they are there, and it said "This 70 cd limit has been designed such that German lamp makers won't bother with designs for the UK market and leave our companies alone"... It would be unacceptable to politicians from Germany! This is another reason why standards should be free to examine by everyone, and should explain all rules... If they do, then this type of nonsense can't happen.
If rules are explained, it will also make possible open discussions, suggestions for improvement, etc.
The law can be written to refer to a standard where technical matters are dealt with. A standard could be included in a law... But some technical matters are needed to understand the law, so there is a dependency... By referring to a standard, that standard can be updated when needed without needing to change the law, though in reality there is no difference of course [ I mean that updating the standard as referenced by the law would be no different than changing the law, and thus using a different updated version of the standard would need to be dealt with in law, by the law makers. So there is no advantage in offloading the technical parts into a standard to try to make things less complicated or even to allow progress without burdening law makers. The only advantage is modularisation, somewhat. And this is why e.g. UK law refers to versions of a standard... ]. By referencing a standard, it becomes part of the law and therefore should be freely available. A law is made by (or rather, approved by, installed by) governments, a standard can be devised by anyone. So therefore my 'law' is like an outline of what should be in a law, with more details dealt with in 'the standard', which is a standard simply by saying it is (fun isn't it :) ).
WHS-2015-bicycle lighting law
Created by W.H.Scholten
( business email: gambiet-fietsen -at- xs4all.nl )
I started on 2015-2-8 with a standard for bicycle lighting, but a law that uses it is needed to give a proper view of what should be in both as they are dependent, so not long after that I started with this law to accompany the WHS-2015-bicycle lighting standard.
In this law I've used material from discussions with various contributors over several years, in particular Charlie Tsai, A.Bradley.
- PV1: 2015-2-17
- PV2: 2015-4-1
A bicycle must have the following devices, all must be approved according to WHS-2015-bicycle lighting standard (for exceptions, see further on). You can see that a device is approved with the marking XXX (think of something :)):
Light-colours of status indicator lamps
The order green/yellow/red is not a good idea for a taillamp, as red will not stand out, and so often a reversal is done, green showing that the taillamp's battery is empty... But that is not a good idea unless this colour sequence is also used for the headlamp, as otherwise you have an interface inconsistency (between headlamp/taillamp). And even then, for a headlamp, and in general, the sequence green/orange/red to indicate full/half-full/almost empty is more logical (as in traffic lights: green = continue, orange/yellow = watch out, red = stop). So that is a better option for a headlamp (and used in the last version of the Saferide 80 for example, at least while using the lamp), but the best way is this:
To give a consistent interface for headlamps and taillamps, in case of a status display using 3 different status-colours:
- The colours in order green/yellow/blue must be used, because it can be used for headlamp and taillamp in the same order, and also because in traffic these colours have a very similar meaning: green = continue, orange/yellow = watch out, blue (emergency vehicle) = watch out even more.
- When charging a battery pack, the colours should indicate how much charge the battery has, in the same way as in use, i.e. from blue (empty) to yellow (middle) to green (almost full), and when the batteries are fully charged, the indicator should blink green.
Example: In last version of the Saferide 80 the status lamps are in fact not status lamps (how full the battery is) but they indicate what you should do. When charging: red = all done (batteries full), you can stop charging. In use: red = batteries empty, stop using the lamp. And thus with charging the meaning of the colours is reversed compared to in use, if one assumes the lights indicate the charge of the battery. I don't like this...
Further the following is required:
Flashing headlamps/taillamps are not allowed. Flashing attracts attention, too much so. Slow moving vehicles (e.g. tractors) use flashing yellow/amber lights and that could work but only in moderation. It only works because there are so few such vehicles on the road! Flashing lights would certainly not work for bicycles in NL, Germany, Belgium as there are too many cyclists. Too many flashing lights = too many distractions = less safety as drivers don't watch what's going on but they are busy watching all the flashing, and it means the flashing is no longer an indicator of an exceptional situation.
For situations in countries where bicycles ride on public roads where cars may drive more than 60 or 70 km/h, and where there are not many bicycles riding on such roads, it could be an option to allow, only there, a flashing yellow/amber lamp at the rear of the biycle, some distance apart from the taillamp, so that distance estimation will not be impaired from it. But note that pedal reflectors are a better option. They attract attention in a gentler way, and still allow distance judgement.Note: For cycling in dangerous traffic (which means where there are large speed differences, i.e. motorised vehicles more than 60 km/h mixed with cyclists) using current rules of various countries: I think a steady taillamp + blinking taillamp is the best thing if one feels the need for flashing. For a headlamp I don't see the point, you can't see with it, and oncoming traffic will be able to see you with a steady light, but also, they are almost always on a different half of the road, and you can evade yourself. With a taillamp you rely much more it working and that people evade you while riding on the same section of the road...
Light devices that are self made, or based on manufacturer made products that are approved, or prototypes from a manufacturer, are allowed to be used as long as they abide by the regulations. They are thus not approved, but legal. In case of self made/altered devices this means the cyclist must be aware of the design requirements in standard WHS-2015 and such lamps and other devices must after modification still be in accordance with that standard. E.g. running a taillamp or headlamp at higher than standard power, then this must still stay within the stated brightness limits. In case of doubt, the cyclist must be able to show he can and did determine this and that his modifications would (e.g. in case of accident and device was destroyed) be in accordance with the standard.
Addition 2015-3-26: For kits sold that need some work but which are in themselves not WHS-2015-approved (have not gone through testing), the buyer must be able to show if asked, why it would be within the rules, and the seller of such a kit must include instructions and complete information on why the kit as sold abides by WHS-2015, and within which parameters it must be used (e.g. power level for LED such that the brightness above the horizon remains within the stated limits). The buyer must understand and be able to explain all that and he may not simply rely on the seller's statement that "it abides by the rules"...
Do (make) it yourself
I included this section as I don't like that DIY is strictly speaking not allowed in e.g. StVZO. If you know what you are doing, DIY is fine.
This standard gives requirements, of what devices need to adhere to be "WHS-2015-approved".
At the moment the requirements and explanations/examples are not separated, that will come in a future version.
WHS-2015-bicycle lighting standard
Created by W.H.Scholten
( business email: gambiet-fietsen -at- xs4all )
I started on 2015-2-8 after an analysis of StVZO/TA, BS-6102-3, and ISO 6742-1. These standards are archaic and/or illogical, partly contradictory in case of TA, do not take physiology nor psychology properly into account, and generally don't explain the reason for the rules.
In this standard I incorporated all thoughts about what I experienced and ideas on how to improve bicycle lighting from the past 6 years, but also suggestions from, and parts of discussions with various contributors over several years, in particular Charlie Tsai, A.Bradley.
- PV1: 2015-2-17
- PV2: 2015-4-3
It is allowed to deviate from the rules if there is some necessity or technical reason. If that happens, the reasons for the deviation must be noted in the approval paperwork.
Headlamps and taillamps are there to see and to be seen, not to divert attention away from everything else on the road. This can happen by virtue of being too bright (blinding oncoming traffic), have too high luminance (ditto, or at least give annoyance from stars in one's eyes), have annoying light colour so not bluish, but esp. no colour changes such as blue/purple/green that some HID lamps/reflectors produce, nor have artefacts that can occur from large intensity fluctuations with miniscule observer movement (so the light output should be fairly smooth). See WHS website: Annoyance caused by lamps).
Headlamps are seen from various distances getting brighter as they get closer. As oncoming traffic rides in separate lanes there is not much need to accurately gauge distances, for overtaking a lot of distance is required, and non-annoyance is not much of an issue. For taillamps the requirements are quite different, and this results in different rules for maximum brightness.
In taillamps the maximum brightness in StVZO is 12 cd/30 cd (normal/brake) which equates for a standard evenly lit car taillamp of 15x8 cm, to about 1000 cd/m^2 / 2500 cd/m^2. A bad bicycle taillamp with bare LED of lets say 2mmx2mm light emitting area would have, for 12cd, a light density of 3.0E6 cd/m^2.
The headlamp in bicycles is allowed to be 70cd (BS), 120 cd (ISO), 200 cd (StVZO), and 6.25 lux at 10 m, i.e. 625 cd for cars in StVZO: Why the differences but esp. why more light than with taillamps? Also, the emitting area is difficult to say exactly what it is, as reflectors and lenses do not shine at all evenly, but I would estimate the surface area of the light going above the horizon to be at most 1/5 of that of the emitting surface. For cars the size of headlamps is around that of taillamps. For bicycles, headlamps are about 5x5 cm these days. This gives a light density of:
- cars: 625 / (0.15*0.08)/5 = 260,000 cd/m^2
- bicycles: BS: (1/0.05) * 29,000 = 580,000 cd/m^2, ISO: 1.0 E6 cd/m^2, StVZO: 1.66 E6 cd/m^2.
So in case of StVZO for a bicycle, the headlamp appears 660 times brighter than a brake lamp in a car... This is not experienced by the eye as 660 times brighter, but it is a lot brighter! And it is in the range of what bare LEDs produce in bicycle taillamps without proper optics. This can cause problems in the eye when it accomodates to this light. The light density from cars, from various experiences, is I would say at the limit where annoyance goes to blinding... And those of bicycles are already over the limit in many cases.
For taillamps it is imperative that you are not blinded nor even annoyed at all, as you must accurately be able to estimate distances and change of distance. 30cd for the brake functionality is already an annoyance to me, and this is no problem normally except when cars are standing still. Then this functions serves no purpose. Normally, you need to regulate speed to about same as the vehicle ahead of you, using that vehicle's taillamps as a guide.
For headlamps it's different. Being noticed is enough, speed differences are large, and you ride on different lanes.
But wouldn't lowering the headlamp limit improve being able to see taillamps? And can it technically be done?
Light gathering: The amount of light gathered is about k/r^2 (k some constant, r = distance from eye to light emitter), so for taillamps often you can be at close distance, and the experienced brightness becomes too high. Experienced brightness drops off because less light of the cone from the light emitter is caught by the finite size eye. For headlamps distances are briefly small, mostly a lot bigger than with taillamps. The eye's adjustment to light is, rough estimate, about 0.3s from my tests, both from light to dark and back. A bright headlamp would impair vision for a large part of that time, after the vehicle has passed...
Headlamps are used to be seen, and to see. For this rules are given for aiming, for the swatch of light on the road surface, the light colour, and that they do not have too high luminance and more.
The 'be seen' part has been given a lot of attention by virtue of DRL (daytime running lights), but which is really already incorporated into any cutoff headlamp by virtue of the fact that headlamps are never fully cutoff simply because that is very difficult to achieve (some standards require a certain amount of light above the horizon, e.g. ECE R113), except that many car headlamps are not cutoff to the right hand side.
A bicycle headlamp may be mounted at most 1.05m (centre of lamp lens) above the road surface. Note that the mounting height is a design factor for a headlamp, see WHS website: Putting a lamp meant for 0.75-0.80 m (fork crown height) at 1.00-1.05 m (handlebar height), and the reverse.
Headlamps must be aimed always such that the cutoff is below the horizon, even stronger, they must actually be aimed such that the highest intensity of the beam hits the ground at a distance of no more than 60 m. (At this distance small bumps in the road are already an issue in causing glare, more seems pointless for bicycles anyway)
The mounting height is a factor at which height it annoys oncoming traffic. If the mounting height is higher, this means the cutoff angle should be lower. This will be taken into account in this standard. This means that a lamp designed for a mounting height for 0.75m may have a slower drop off of brightness from max lux to less than 2 lux (for example, exact value to be determined), than a lamp meant for 1.05m.
This means a lamp designed and approved for a mounting height of 0.75m, may not be mounted on the handle bar. Conversely a lamp approved for mounting on the handlebar, may be mounted on the fork crown at ca. 0.80 m.
Therefore there will be 3 lamp beam approvals:
So a lamp of category L3 may be used at a mount height of anything up to 1.05m, a lamp of category L1 may only be used at a mount height less than 50 cm.
For aiming to keep correct, it is essential that the mounting method is secure even when it rains. Rubber bands are certainly not suitable for this purpose. Some type of bolt/screw that fastens the mount around the handlebar, if mounted on a handlebar, is probably needed. The testing method will be to make the handlebar and lamp mount wet, and apply force as customary for the headlamp in question: press on it with force that will be needed to activate buttons or insert/remove a cable for batteries, or a reasonable force of accidentally touching the headlamp.
Aim with a bicycle with suspension must be done in the customary riding position of the cyclist, on a flat road, such that the lamp is aimed properly for most situations.
If the lamp mount is separately available in various versions, then each lamp mount must be tested for that particular combination to be WHS-2015-approved.
More to come... XXXX
Beam with cutoff:
XXX To do: Give description of requirements: On the ground, wall projection, and more, to come...
Beamshape on the ground can be calculated from the wall shot, when specifying a mount height, and lamp angle. The beam must be sufficiently wide at 20m-30m. Say 5 m wide? Intensity on the wall shot: This is hard to specify, because depending on aiming, what part of the beam the width at say 30m comes from, depends on how far you aim it.
High beam/low beam on bicycles: Allow a high beam?
Definition: high beam = any beam that has more light above the horizon than acceptable as a cutoff beam or which has a cutoff at a higher position than the low beam, which is defined to be the the beam from the mode of the lamp that gives the lowest position on the wall shot, of the cutoff.
Option 1: No high beam allowed, and the cutoff limit must be in the same position in all modes of the headlamp. Note that in StVZO/TA the cutoff limit-change in different modes is not taken into account in the approval process thus in effect allowing a high beam, but a low beam as high beam is not optimal, in particular it causes more glare. This is a flaw in StVZO.
Option 2: Allow a high beam (in addition to a low beam, not as the sole headlamp!), with requirements described after the considerations:
High beam vs. low beam
For bicycles a high beam, so with more light above the horizon than the cutoff allows, is comfortable to ride with, but it is really only needed for mountain biking, or for high speed descents.
1. For the latter 2 you need a lot of light!
2. With high beams that are not cutoff as required, or high beams that are actually cutoff beams with the cutoff point in a different (higher) position than the low beam, then if they are not powerful enough, I estimate that cyclists will have the tendency to leave them on in the high mode, possibly even forgetting it is a 'high beam' that blinds or annoys oncoming traffic. This happens enough with mopeds, why would it be different with bicycles?
That the (high and low) beam is weak on mopeds is a reason for not switching to low beam, so there is not enough difference between low/high beam and not a feeling of 'this is a lot of light, need to dim it for oncoming traffic'.
For motorists it's different for various reasons: needing to get a driving licence and learning the rules is one of those, getting the high beam of other motorised vehicles in your face as a warning, if you don't switch to low beam, is another reason...
Therefore: The high beam needs to be strong, and there needs to be a clear difference between low- and high beam.
Problem: The problem remains that there may not be a regulating effect for the use of the high beam, except on shared roads with motorised traffic. Only then will cyclists using a high beam be notified with flashing the high beam, that they should switch their high beam off, as most cyclists don't have such a high beam (esp. for countries like NL, DE, BE)
Because of these considerations, allow a high beam only if:
These should do almost the same as what taillamps do at night, but for daytime at the front. So DRL is only allowed to make oneself visible (if needed), not to attract (too much) attention! Therefore point sources (high luminance) are NOT allowed. See for more on this issue further on with a new measure of how to identify proper light distribution (using both luminance, and luminous intensity).
My main complaint about DRL: It attracts my attention, attracts it away from everything else! This does not make the road safer, it makes it less safe! The DRL from many cars is almost as bad as B&M's 'visibility by being annoying' DRL...
Taillamps are used only to be seen. For this rules are given for the beam, intensities and angles, the light colour, and that there is not too high luminance, or rather, a too high light density, and more.
The taillamp must shine a steady light, flashing or cyclically varying intensity is not allowed. A temporary brake signal is allowed with triple the normal brightness. If a taillamp can be programmed (by button pressing or any other way) to have a flashing mode, it must be programmable such that the flashing mode cannot be selected normally. This must be done in some way that is non-trivial, or by setting a switch inside the taillamp.
This is at the moment a non-technical requirement and thus should be in the 'law' rather than the standard? (this is one of the problems one encounters with modularisation). But it may be that we need to deal with it here, just as with headlamps: Does the taillamp need to be different depending on mounting height?
A DRL taillamp is just the regular taillamp, as it is about being seen...
So see the previous section. Perhaps for daytime intensity could be higher, but I think it's not needed. For DRL the headlamp is most important anyway.
The bigger the headlamp, or rather the light emitting area, the less strong the intensity will be in any spot in the eye, when getting that light direct into the eyes.
This means that if the light emitting area is bigger, the amount of light in lux or cd may be proportionally higher. In reality this must be measured to see if the design conforms to limits given. Precise limits to be determined/specified.
Luminance is the emitted light devided by the area of the emitted light. This is relevant for glare and annoyance because the eyes have lenses and spots are mapped to spots. If a spot of some small size emits too much light, then it will be experienced as a spot that is too bright on the retina, which is experienced as annoying. But there needs to be some area large enough for this to be truly annoying.
The issue of getting blinded is from differences in intensities, and the difference with the rest of the things you see at night is in situation 3 far too high even though the amount of light in situation 2 and 3 is the same... The eye accomdates to the brightest light (highest intensity on the retina) and thus such overexposure must be avoided [ add example of black phone with red tape, then switching screen on which decreases the perceived brightness of the red tape. ]
The further you are from a light source with high luminance, then at some point it will not be annoying any more. The cause is likely from a variety of factors: distribution of light across more receptors in the eye, but possiblly also atmospheric influence, and motion of emitter and receptor.
For this reason the annoyance must be defined beginning with the smallest light source (that is equi-luminous on the entire light emitting surface) that gives annoyance at a relatively small distance of say 5 m, using a given not too high lumen rating, of say 1 lumen (this is likely already a too high light output), where the light emitting surface is A.
Then: ∫A IdS = 1
Now take a lamp which has a light emitting area L, then if somewhere in that area L there is an area of size A (approximating a circle, or just a square to keep it simple), of which , ∫A IdS ≥ 1 then the lamp will annoy.
There can be additional measures, depending on the eye's response to smaller vs. larger light emitting sources... It could be that for a larger area, a smaller intensity (so less light from the original size surface A) already annoys. So then a second measure (or one of a range of measures) could be: annoyance = true if ∫A2 IdS ≥ 2, where A2 is a larger area, say 5 times as large as A. The exact values of this must yet be determined...
Measuring the light emittance to determine whether it stays within the non-annoyance limits, can be done by measuring the amount of light into a specific direction coming from a specific position on the light emitting surface, using an black screen with a small hole in it, and a receptor some distance behind it. This receptor then measures the light going into a specific spatial direction coming from a spot on the light emitting surface on the line perpendicular to the screen, and going to through the centre of the hole in the screen.
Visibility is also determined the same way! After all, the intensity needs to be high enough on the retina, to be seen (receptors stimulated enough), but not stimulated too much from a too high intensity (which annoys), and the surface must be large enough, to be seen (as in: the dot on the retina large enough so that the brain notices it). Here it is easier to just calculate the luminance, if the surface area is of reasonable size, and then check for uneven light distribution.
Bulbs have a low light output and short lifespan (50h?). The cyclist is required to carry spares with him for lamps using such a light source (and the tools to open up the lamp) or any other light source that has a lifespan of less than 1000 h.
(2 h per day 365 days per year is 730h, that is already a lot of nighttime cycling in one year, so for this reason I've chosen 1000h as a nice round number).
Better options are e.g. LEDs with nearly unlimited lifespan. As LEDs have nearly unlimited lifespan they need not be exchangeable as opposed to bulbs, they can be fixed permanently in the headlamp/taillamp, but if the PCB with LED is removable/exchangeable, then the PCB must be marked as being a specific type by the manufacturer of the headlamp, and defective PCB/LED units must be replaced with identical units (PCB size, LED position, LED type). The LED may be of higher efficiency, or of other colour temperature, but not of different LED type/die size/emitting angle as that would invalidate the approval of the tested combination of LED+reflector/lens.
For any other light sources the same reasoning goes: Replacements must give the exact same distribution pattern on the road (and on the wall shot) for headlamps, and the same beam pattern for the taillamp, and therefore the replacement light source must give the same light distribution from the same position.
Note for the headlamp that 'white' LEDs have a colour spectrum that is not optimal for several reasons which can be mitigated by choosing the right colour temperature. See section 1.1.4 for this.
Power sources are:
It must be clearly indicated on headlamps and taillamps which power source they need (battery/type/voltage, dynamo type, special box running from dynamo with outputs for headlamp/taillamp).
Dynamos may be any power. The typical 3W/6V standard will be specified as a standard, but other types are allowed. More power can be extracted from dynamos when desired using non-resistive loads...
Lower power dynamos are not a very interesting concept, nor are they needed. Cyclists have plenty of power, even weak cyclists, for a 3W/6V dynamo/lighting system.
Should there be a demand for efficiency? This is really not an issue of much importance to the cyclist's speed, so it would only be needed to weed out bad products, but this is more a task for reviews.
Power specifications: allow only ≥3W? (measured with resistive load)
Lamps that run on batteries, must be designed for rechargeable batteries. Reason: Non rechargeable Alkaline batteries cause reliability problems because of leaking of acid which corrodes contacts and electronics which causes unreliable function, and rechargeable batteries are better for the environment. Energy loss is not an issue even for seldomly used lamps, when using low self discharge NiMH batteries so the use of Alkaline AA/AAA batteries has no advantages. Making the lamp compatible with non-rechargeable batteries for 'just in case' is allowed.
It is not allowed to ride without light when it's dark or otherwise when conditions demand it to be seen (such as mist). As people tend to not charge batteries until it is too late, and as cyclists tend to ride on without light if that happens, for headlamps and taillamps that operate on batteries only, there needs to be a backup, such as:
The cyclist is required to carry such a portable charger or spare batterypack or spare battery-cells, whichever can be used with his lighting system, with him on all trips because it can never be predicted when lights are needed, even during the day (e.g. thunderstorm) and the reasoning as before then goes.
A cyclist need not take along a backup such as spare batteries nor a powerbank (battery powered charger) as the dynamo will always provide power when needed.
The power source's power can be converted to whatever the headlamp and taillamp need by electronics. Unlike old systems without electronics (dynamos and bulb headlamps/taillamps), the voltage/current can in modern systems be converted to whatever is needed by regulating electronics for the light source. Setting limits on operating voltages or batteries to be used is therefore pointless, except for the safety for the cyclist. If the system somewhere generates voltages that can give a shock, these must be internal (in the box for the electronics, or in the headlamp etc.), well shielded, and safe from ingress of water.
Dynamos' power output varies with speed, and the electronics used to power the headlamp/taillamp must take this into account and protect the electronics with a suitable device such as 'overvoltage protection'. This protection must be able to withstand the increased power and voltages of output of at least 70 km/h for the dynamo it's intended for (I specified 60 km/h at first, but with big hills 60 km/h is not so hard to reach, so I set it now at 70 km/h to give some margin which should make it safe to use in almost all situations). Exact speeds for which the electronics are suited (with type of dynamo it's used with) must be noted on the lamp/electronics box and in the manual.
If a headlamp can work with a dynamo that produces more power, and is intended for use with such dynamos of higher voltage and/or higher current, than a standard 6V/3W/15 km/h dynamo can provide, it must indicate design limits. Essentially this means design limits on dissipation of excess power, as dynamos are not constant voltage, this depends on the speed of the cyclist. A maximum speed for a certain dynamo type to be used, must therefore be indicated on the lamp/electronics box.
Headlamps will generally need to specify (on the housing) which power source they are to be used for, unless the power source is internal (batteries). This means a alternating current (direct from dynamo), or direct current from battery or from separate regulating electronics.
If a headlamp and taillamp are wired together to the dynamo, one can function without the other, such that if one fails, the other still works. However, both are required for safety (esp. to be seen), and thus walking is the only allowed option if the electronics in one of them fails. Therefore to have them work separately, with separate electronics, is no advantage except to prevent the taillamp from being damaged. For shared electronics, taillamps can be wired from the headlamp. This can give simpler taillamps with almost no electronics, and no duplicate excess power protection.
So for taillamps: 1. Via headlamp, 2. Parallel with headlamp.
In reality dynamo taillamps that are made today, which usually comply with the German StVZO regulations and sometimes those of other countries, can be used both ways, and when they are attached via the headlamp, it means they are switched on/off together with the headlamp, but also it guarantees that the taillamp only works if there is proper contact, and no broken wire, between the dynamo and the dynamo-headlamp; and thus the overvoltage protection in the headlamp will protect the taillamp that is wired via the headlamp; this is not necessarily so if they are wired in parallel). Many taillamps don't include excess power protection, so if the headlamp fails, esp. the excess power protection circuit that will be worked harder if the headlamp's light source is not working, or if the overvoltage protection circuit fails, then the taillamp can also easily fail. Wiring the taillamp via the headlamp is safer, as the overvoltage protection may not work if the wires to the headlamp don't make good contact with the dynamo.
Types of headlamp:
Types of taillamp:
It must be specified clearly that a headlamp is meant for battery, dynamo, or a special other system.
Standlight means that the headlamp and/or taillamp still shine for some time after the bicycle stops. There is no requirement for a standlight as it will only be needed while standing still on public roads, and that means in places where there are traffic lights or crossings, where speeds are low and all participants in the traffic should watch out, and reflectors show that there is a cyclist, but a standlight is still useful to show that there is a bicycle on a public road. As cyclists will assume they are well visible with a standlight, in typical situations such as waiting for a traffic light, the minimal duration for standlight is 4 minutes. But it may be switched off manually after the cyclist dismounts, e.g. to park his bicycle.
The energy storage may be charged at any time, as long as the headlamp and taillamp give enough light to ride safely. The headlamp/taillamp must give light even with fully depleted batteries, taken out batteries or defective batteries.
A battery powered headlamp or taillamp, must have an indicator showing that the energy left is only enough for ca. half an hour. Perhaps also for the taillamp, an audible signal (idea by A.Bradley)? (because you don't often look to the back to check the taillamp!)
Battery powered systems must be designed for rechargeable batteries, and the status signal must be designed for such batteries. So if a taillamp uses 2x AAA batteries, then the status must be designed for rechargeable batteries of 1.2V and not Alkaline 1.5V. The use of non-rechargeable batteries is discouraged.
Dynamo or dynamo/battery systems with cable to the taillamp must have a status indicator at the front (on the headlamp or some separate box) that shows whether the taillamp is working. The light from the taillamp could be checked by glancing back but this is better, and safer.
It must be possible to easily (non-destructively!) open up these devices, so that a cyclist with enough skills, and if needed tools (such as a soldering iron, device to press in bearings or cups etc.) can perform maintenance/repair, for example to replace parts that can wear out (such as a standlight capacitor for the headlamp/taillamp, bearings in dynamos). If special tools are needed, these must be made available by the manufacturer for a reasonable price.
With reflectors are meant actually retro-reflectors, which send back light to around the direction from which the light shining on them came.
A reflector at the front is not as useful as at the rear, after all, active lighting makes you visible, so reflection is only a backup. With taillamps, you may overlook for a while that it doesn't work, with a headlamp this is very unlikely, but possible within a city with enough streetlighting. So a front white retro-reflector is required of at least 10 cm^2. This size is chosen as it's not that big, so can be accomodated on headlamps, and not too small to be not noticeable.
Front reflector sizes: Examples
I did a test with reflectors from:
- B&M Avy, ca. 6 cm^2
- Herrmans H-one S, ca. 10cm^2
- Philips Saferide 60, ca. 10cm^2
I felt that the small reflector was just a bit too small. Also 10cm^2 is compatible with Swiss law, this is perhaps this is why the Philips and Herrmans headlamps have such size front reflectors, but it seems a reasonable size anyway.
For white front reflectors, surface reflection (see the following section on rear reflectors) is less bad than with taillamps, but it can cause glare into irrelevant directions thereby attracting attention, so here too, one of the 3 options to reduce reflection as in the rear reflector, must be used.
A rear red retro-reflector is required of at least 15 cm^2. It may have any shape [ except a triangle?, as that is used to indicate to take care at places where a vehicle could be placed for repairs, for example, but as noticed earlier it could be useful and a triangle could then be interpreted as 'slow or stopped vehicle ahead'. And what about say a arrow shape? (also note that I thought shape of small objects such as a taillamp is hard to see anyway, at say 30m already, so perhaps the shape is irrelevant) ], as long as it is one contiguous area.
Rear reflector sizes: Examples of Z-reflectors
The Z-reflectors in some taillamps: (note that StVZO says bicycles need a 'large' reflector, but what 'large' is, and thus the size, is not specified...)
- Herrmans H-track: 4,2*3.6 + ca. ellips 32x36mm = 15 + 9 cm^2 = 24 cm^2
- Philips Lumiring: 6.2 * 2.9 + circle 2.9 cm diam = ca. 24.6 cm^2 - logo [ rectangle of 4.5mm*25mm ] = 23.5 cm^2
- Line plus: 8,5*2,0 = 17 cm^2
- Solo ca. 8,8 *2,0 = 18 cm^2
- Lineo: ca. 8,3*3,0= 24,9 cm^2
Red reflectors must minimise surface reflection (white light from a following headlamp reflecting back as white light), into any specific direction, by using one of these options:
White surface reflection: Examinations, experiences
I deal here with taillamps, but this issue is present too in headlamps but it's less of an issue as headlamps shine white light and usually the distances at which you see the reflection, are bigger than with taillamps.
I've experienced strong white surface reflection from shiny plastic of flat taillamps a lot, when riding with a powerful headlamp behind other cyclists (at close distance)... This is annoying and should be dealt with.
Interestingly this issue is mentioned in StVZO/TA, not as a problem to be solved, but as something to be worked around to measure the reflective properties of reflectors...
I first thought about how to get rid of this (or rather to prevent a strong reflection into 1 direction, distributing the light is fine) with a matte surface, or a curved surface. I noticed long ago that bicycle computers with curved surface are almost not affected from reflections that can make the LCD sometimes unreadable on those with a flat surface, and here it applies too. The simplest way is a curved reflector without anything over it. If anything goes over that for some reason, e.g. to protect the reflector, it must be a curved red translucent surface, as in the Plateo.
- The Spanninga Lineo has a curved clear surface over the flat reflector. It works well while not losing visibility, but it still has a strong secondary surface reflection, from the reflector behind it (as the reflector is flat).
- The Spanninga Plateo is better, it has a curved surface, from red plastic, which may be slightly less efficient than clear plastic, but the white surface reflection is not strong, and when you notice secondary surface reflection (from the reflector surface which is flat or almost flat), it is red and not as strong as with the Lineo.
- Basta (Axa) Ray: fully curved reflector surface with nothing over it, giving almost no strong white reflection into any specific direction. This is at least as good as the Plateo and it is simpler...
The manual must include
Requirements on packaging for example showing beamshape? Measured light output? Colour temperature?
This means sending in some lamps, dynamos, reflectors, and fill in some forms! And paying for testing...
Cost of the approval process: I have no idea, this costs apparently €2500,- for StVZO approvals... So that will be an indication.
Last modified: 2015-3-3