UK: Road vehicles lighting regulations

I received various useful information from a reader of my site, about the UK situation, and he thinks the British rules may be dead as manufacturers don't care about them, and that e.g. intensity rules may be written directly into law instead of into regulations. Regulations lead to a test (an independent test is apparently not necessary but if the manufacturer does this itself, then you can assume it agrees with the rules, and if anything happens, they will be responsible...) and an approval sign so you know a lamp is good by just checking this sign. Doesn't it mean that by writing specifics direct into the law, that the only way to be sure about validity of a lamp is by testing? Surely the police aren't going to do spot measurements of bicycle headlamps when they suspect it might not to be legal? It would be a lot of extra work for them... And of course there is no MOT for bicycles... This would mean in practice I presume (which one of my readers agreed with and gave an example of), that tests will only be done after something has happened, i.e. after an accident, to determine if a light or other part of the lighting system caused a problem.

Here is some information:

And here are the RVLR:
with amendment (about flashing lamps etc.):

Then we have the British Standard, which has to be purchased just like StVZO (though you can ask for the StVZO stuff, at least the updates, for free if you pester people in government...). The British standard can be viewed in public libraries.

Does anyone want to spend some time in the library and look up the headlamp rules? I'd be interested in what it says about them...

4-8-2013: Aha, I got my hands on the regulations, BS6102-3-1986! (with amendments 1,2,3 dated 1 Sept. 2003). Cool. It's interesting how much more clearly the UK's RVLR text is organised than StVZO, with a clear numbering system instead of the mishmash used in StVZO. The middle of the beam is also defined in RVLR which it's not (at least I didn't find it) in StVZO. More on these regulations to come...

BS6102-3 mentions that the rules therein are based on ISO 6742-1 and when I looked at the document of ISO 6742-1 that I found (in Czech) it looks very similar in structure, pictures and tables...

The UK rules, relevant for bicycles:

Index to summary/analysis of BS 6102-3

I follow BS6102-3 in its numbering/order:

BS 6102-3:1986 Cycles: Part 3: Specification for photometric and physical requirements of lighting equipment

BS 6102-3:1986 Foreword

Here is mentioned that the rules are based on ISO 6742-1 with exceptions:

1. Luminous intensity requirements of ISO 6742-1 for the headlamp have been adopted, but additional test points have been specified above the horizontal plane.

2. No allowing of yellow light for headlamps contrary to ISO 6742-1.

3. For the taillamp higher luminous intensity requirements than in ISO 6742-1 over the whole range of test points, with additional test points at 5° from the vertical and horizontal planes. And the vertical cone of light from the rear lamp has been restricted to the forward shining part of the cone. (this is similar to what StVZO requires).

BS6102-3:1986 Introduction

Interesting point at the start: They mention they assume the headlamp is 'as usual' mounted on the headtube [ which is actually, by now in 2015, an old fashioned method, used mostly on old style city bikes with headlamp mount on the top of the headtube bearing ] and that the beam centre will hit the road surface at a distance of 16 m and that this determines position 'A' on the testgrid at 3.5 degrees below the horizontal. [ it's a relief to read these rules, which are so much more clear than StVZO! 2019-4-8: But still insufficient of course as hitting the road at a certain distance means nothing unless you specify how, and that should be done via the cutoff, though that too is not enough, as I eplained on my site in some places (how quickly the beam drops off to the cutoff, and I will deal with this problem in my WHS-2019 lighting standard. ]. From this one can calculate that they assume a headlamp is mounted at a height of ca. 0.98 m. They further say this distance is determined by braking distance + reaction time... [ good to see some logic and explanation! ]

BS6102-3:1986 1. Scope

These rules are about the photometric and physical requirements, test methods, markings.

BS6102-3:1986 2. Field of application

Bicycles on public roads.

BS6102-3:1986 3. References

BS 397, Primary batteries. [ Note: Primary cells are non-rechargeable batteries, e.g. alkaline. ]
BS 5101, Lamp caps and holders together with gauges for the control of interchangeability and safety.
BS 5466, Methods for corrosion testing of metallic coatings.
BS 5466-1, Neutral salt spray test (NSS test).
BS 5932, Specification for sealed nickel-cadmium cylindrical rechargeable single cells.
BS 6102, Cycles.
BS 6102-1, Specification for safety requirements for bicycles.

CIE Publication No. 15 Colorimetry: Official recommendations of the International Commission on
Illumination (CIE) 19711).

BS6102-3:1986 4. Definitions

Of what a bicycle is :) And just about anything else that's needed for the rules.

Notably they define the beam centre: this is defined as the area which has a intensity not less than 80% of the maximum intensity of the beam, of course, an area is not a point, so this still leaves room for interpretation issues if the area of such intensity is big and possibly non symmetrical... What is then the 'centre' (of this centre-area)?

Commentary about 'beam centre' for headlamps

For the time of this standard, and still with low lux headlamps as of 2015, having some blob on the ground at a reasonable distance is a logical thing to define, but with higher power lighting, the only proper way to aim a lamp, is by its cutoff. I've recommended this recently to a company, for inclusion in the manual... So a better new standard (should I write one, and put it on my site as an example of what proper rules would be?) would include 2 methods of aiming: It it's a weak lamp, aim a blob of light on the ground, and 16 m seems a fair distance for such lamps and for people using such lamps. If it's a strong headlamp, aim the cutoff below the horizon.

Note from a reader: There is no aiming requirement in BS, nor that a light must be pointed such that it doesn't blind others.

Correct, and in StVZO there are 2 rules: The aiming requirement in StVZO.§67 (which is specifically for bicycles) which doesn't make sense and with which you could aim the lamp almost any way you want really, as I've shown on my page on StVZO, and the general rule (not just for bicycles) in StVZO.§66a which says that lamps may not be blinding (StVZO.§66a are general rules, for all vehicles, though not always e.g. StVZO.§66a.4 which says that all vehicles must have 2 red reflectors at equal height, but they don't mention that this is not true for bicycles! These sort of issues a big problem in decoding what is meant in StVZO; some rules overrule others and this is mentioned only in some cases). Again as with taillamp brightness, could there be a general rule in UK law that's not in the bicycle rules that regulates this somewhat, as it is in StVZO?

2015-1-30: More information from the same reader: UK rules on dazzle: There is a general forbidding of dazzle in law (no technical properties given):
Regulation 27 gives "Restrictions on the use of lamps other than those to which regulation 24 refers". So a BS6102-3 headlamp should be aimed downwards such that it doesn't blind others, so proper use as a "dipped lamp". But there is nothing to forbid a cyclist having a switchable main beam.

BS6102-3:1986 5. Photometric requirements for headlamps

Conversion from cd to lux: Because of the measurement definitions these can be converted with lux = cd / (dist^2). As StVZO measures at 10m, this means the equivalent lux values are 100 times smaller. I will include lux values thus calculated.

The beam for a headlamp is similarly defined as in StVZO. With a bright spot below a line H, and above the line luminous intensity may be only 70 cd or less (≤ 0.7 lx).

Point 'A' lies 3.5 degrees below H, and it must have a brightness of at least 400 cd (≥ 4.0 lux), or 0.8 Imax (max measured intensity of the beam, so the maximum need not be in 'A'), whichever is greater. Note that StVZO requires a minimum of 10 lx...

'A' is surrounded by 4 spots 'B' 1 degree above/below and 4 degrees to the left/right of 'A', where brightness must be 0.5 Imax or more.

1.5 degrees above H are 5 points: 'F' (20 deg left/right from 'A'), 'E' (10 deg left/right from 'A'), C (right above 'A'): Intensities must be at least: 0.025 cd (≥0.00025 lx), 0.075 cd (≥0.00075 lx), 0.25cd (≥0.0025 lx). Note the they must all be lower than 70 cd (≤ 0.7 lx) because they are above the horizon.

Then 7 degrees above H are 2 points 'E2', 4 deg left/right from 'A'. Intensity must be at least 0.075 cd (≥ 0.00075 lx). And again: lower than 70 cd (≤ 0.7 lx) because they are above the horizon.

Note that the cutoff requirement is more stringent than in StVZO, the latter demands that there is 2.0 lx or less, at 3.4 deg or higher from HV (the centre point), and in StVZO Emax (value of max intensity of the headlamp) should lie on the line though HV but may be a bit to the left or right. One of the 4 points 'B', the one above 'A' but below H could make the problem of making high lux headlamps even worse (the challenge is to make the lux rating go from max to almost nothing in small distance), I'd need to check distribution patterns of actual headlamps, but, this point is a stupid requirement in BS (and in ISO).

The brightness values BS 6102-3 5 requires above the horizon are probably meant to illuminate traffic signs. But they are met in reality probably more by accident, or rather by natural effect of any headlamp not being perfect and certainly not having a strict cutoff from max to really zero, than by design, in any bicycle headlamp. But note that ECE has similar requirements of light above the horizon. The Philips e-bike lamp (which complies with ECE R113) as shown during the bike light day 2012 has a strip of light above the horizon, and I asked whether it was below 2 lux, which they said it was. It was, they said, quite hard to get this beam pattern and also why they used Altilon LEDs...

They say that the measurements must be done at sufficiently large distances for the inverse square law to be effective. Note the section I wrote about this further on in the taillamps regulations (BS6102-3:1986 6) about this. This is also important for headlamps, especially the 'to be seen' lamps, or DRL (daytime running lights) which can be very annoying, such as B&M do in their headlamps which are a form of 'visibility by being annoying' which I consider unacceptable.

The test method is described including a little about the measurement, size of receptor, linearity of photometer etc.

And the colour of the lamp is checked which must be within a certain area on the colour chart.

BS6102-3:1986 6. Photometric requirements for taillamps

Minimum brightness values in various points:

          | -110 deg | -45 deg  | -10 deg | -5 deg |   0 deg |
  10 deg  | 0.025 cd | 0.075 cd | 0.25 cd |        |         |
   5 deg  |          |          |         |   2 cd |         |
   0 deg  |          |          |         |        |    4 cd |

This table should be mirrored up-down and left right to get all the points, so this is one quadrant.

In the centre the required minimum values are the same as for StVZO for vehicles other than bicycles, i.e. 4 cd. Comparing to StVZO (assuming TA.14b overrules TA.14, note that the taillamp section in StVZO is a mess, contradictory, unclear etc.):

Strangely I don't see a maximum brightness for taillamps, is it mentioned in a general rule (in RVLR, not in BS 6102-3) that bicycles also must abide by? Or did I overlook something? Well, it seems I was right, there is no brightness maximum. I would have thought that the rule makers, despite technical issues in making too-bright taillamps for bicycles at the time this standard was made, would not have allowed a brightness more than car taillamps, and certainly not equal to a car's brake lamps. It could be that a general rule in RVLR sets a maximum but I have not checked.

BS 6102-3 says that for measurements, the point A must be in the beam centre (the beam centre is generally defined in section 4, so for both headlamps and taillamps). They further say that a deviation of all points except A of 15 degrees is allowed, i.e. they mean the point where the required value of the given test-point is reached may deviate up to 15 degrees (horizontal and vertical?).

The taillamp must have a visible indicator shining light forward/upward just as in StVZO, with an intensity of at least 0.02 cd (in StVZO it is larger, 0.025 cd).

They say that the measurements must be done at sufficiently large distances for the inverse square law to be effective. Note: This statement but also the use of cd as visibility and esp. to prevent annoyance from dazzling lamps is not enough! A new type of measurement should be done, which I mentioned to a reader with whom I've discussed various issues over the past year and half and I will soon write this up. This different measurement would be a hybrid of luminance and luminous intensity, or perhaps luminous intensity (cd) is enough, but, only when explicitly mentioning the measurement equipment such as size of photoreceptor area and how well it can only select light going into specific directions! I will add something about this on my site soon, end of January 2015 or early February, after analysing the ECE rules for cars, e-bikes etc. (Update 2018: Later in 2015, in my standard, I suggested using cd/m2, which takes the emitting area into account and means no need for directional measurements)

The test method is described including a little about the measurement, size of receptor, linearity of photometer etc.

And the colour of the lamp is checked which must be within a certain area on the colour chart.

BS 6102-3:1986 7. Generators

Interestingly, the rules do not specify voltage/power! Only that the manufacturer sets specifications, and the following goals must be met using a resistive load: At a speed of 15 km/h the output voltage must be from 0.85 to 1.17 of the specified voltage, at 30 km/h from 0.95 to 1.17 and at 5 km/h from 0.50 to 1.17. Not setting any power output requirements, only a range of ouput voltages (and thus power) relative to the specified voltage for several speeds makes sense, except for interoperability with headlamps/taillamps from other manufacturers.

BS 6102-3:1986 8. Batteries

BS 6102-3:1986 8.1 Primary (non-rechargeable) batteries
Batteries need to comply with BS 397. (So what does that say?)

The headlamp must produce at least 100 cd in test point 'A' at the 'final measured voltage'. For taillamps not less than 22% of initial value in test point 'A'. The testing method specifies testing the lamp for 10h, so it seems any headlamp/taillamp using non-rechargeable batteries must work for 10h on the cells it's designed for.

BS 6102-3:1986 8.2 Secondary (rechargeable) batteries

It starts with a note about NiCads which are standardised (but in 2015 have been obsolete for years...), and other types are not standardised.

Here the same requirements as for 8.1 about brightness but the operating time is manufacturer defined...

BS 6102-3:1986 9. Switch performance

The switch for battery powered lights must have positive action, switching must not cause flickering and must still work properly after 5000 switch operations. [ Seems reasonable :) ]

BS 6102-3:1986 10. Environmental tests

Vibration testing for headlamps/taillamps. A vibration machine for testing is defined in appendix A...

Temperature testing for headlamps/taillamps/generator.

Moisture resistance tests for headlamps/taillamps/generator.

Corrosion resistance tests for headlamps/taillamps/generator.

Fuel resistance testing for headlamps/taillamps (testing with a mixture of 70% n-heptane and 30% toluene, the same as in StVZO)

BS 6102-3:1986 11. Marking

On the headlamp and taillamp must be marked: The power supply and light source to be used [ irrelevant for LED based lamps I presume, as there are no standards for LEDs being measured independently from reflector/lens, see also StVZO about this issue ], an idenfifying mark for manufacturer, and "BS 6102-3".

+ according to BS 6102-3:1986 12. Instructions for a lamp, the reference numbers of filament lamp and battery [ if it's a battery lamp! ] should be marked too. [ Why didn't they write that in this section? This is my first disappointment about the BS document ;-) ]

On the generator must be marked: The voltage and power output, an idenfifying mark for manufacturer, and "BS 6102-3".

On battery packs, or on lamps with batteries internal, must be printed "MAXIMUM USE BEFORE RECHARGING X HOURS" [ not sure if using all capitals is really required or that just caps lock was stuck on the BS writer's keyboard ;-) If it was intended, then they should be told that a sentence with all caps does NOT make it more readable nor even more noticeable, on the contrary. ], where X is the number of hours the lamp can function at the required intensities (see BS6102-3:1986 5. Photometric requirements for headlamps and BS6102-3:1986 6. Photometric requirements for taillamps), with a new and fully charged battery.

BS 6102-3:1986 12. Instructions

[ This section is yet another way in which these rules are better in being more clear than StVZO. In StVZO some prescriptions for the manual are only given to the permit holder, in the approval details (when you receive it)! Ludicrous! E.g. the document of Dosun's D1 StVZO approval is interesting for the details of what they must include in the manual, which cannot be found in the StVZO documents. Perhaps the details for manuals are not included in StVZO/TA so that they can be easily changed, without changing the rules text, however, the manuals are dependent on the rules, and so only really changes in the rules need to give changes in the prescriptions for the manual ]

The manual must contain:

1. For lamps powered by primary batteries [ non-rechargeable batteries ], or dynamo: How to fit them, how to use them, information on replacement parts and how to install those.

Further, information on the light source and batteries to be used for optimal performance.

2. For lamps powered by secondary batteries [ rechargeable batteries ]: How to fit them, how to use them, information on replacement parts and how to install those, type of battery charger, recommendation for charge duration, warning against overcharging or anything else that might damage the batteries, expected life of the battery and that the user should do an annual check for battery deterioration, information about loss of charge when the battery is not used for some time..

BS 6102-3:1986 Appendix A: Vibrations test machine

This has a description with picture of a vibration machine for testing headlamps and taillamps...

BS6102-3: Summary: Headlamps

To come soon...

BS6102-3: Summary: Taillamps

To come soon...

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