J
Just Zis Guy
Guest
OK all, having discussed it once or twice (ha ha) I offer you Chris Juden's final submission on the
RVLR consultation.
Before you read it, a call to action: *please* respond to this consultation.
Why?
Because it matters. If sufficient people respond we might see an end to the stupid situation where
you can have a Cateye Stadium 3 on the front, a RealLite on the back, reflective jacket, cuff bands
and ankle bands, and still be breaking the law - but a 1980s Wonder Light, a .6W tungsten rear light
visible from 20 feet on a good day, wearing black from head to toe but with pedal reflectors, and
you're perfectly legal.
We are all of us I think responsible cyclists - we all (as far as I know) use lights and at least
think we're obeying the law - but the law is perverse and your lights, however good, may not be
legal. This might be because the writing on the battery is the wrong size! Even if you ride out with
a set of Lumicycles you're still not legal unless you carry a "BS Approved" (and functionally
worthless) front light. What does this mean in practice? It means those weasels at the insurance
companies can claim contributory negligence when some blind ****** knocks us off. It's happened
before and it'll happen again, unless we get the regs changed to recognise that functional lights
are what matters, not a standard which is irrelevant in any other country.
For the DfT page on the consultation, please see
<http://www.roads.dft.gov.uk/consult/lighting/index.htm>
You can respond, according to Informed Sources, by writing to your MP, writing to the DfT at the
address on their website, or by email to catharine.parton(at)dft.gsi.gov.uk [see, I've even tried to
help her avoid the spammers!]
I particularly recommend that you address in at least some detail any issues about which you feel
strongly or have particular knowledge - for example, the futility of pedal reflectors on 'bents, or
the regulations on dynamo lights which don't take into account standlights. My response is linked in
Chris'email below, so I must be doing something right!
Oh, and one last thing: Chris' documents all have a contact email address - chris.juden (at)
ctc.org.uk. If you are a CTC member, it's useful to enclose your membership number on any email you
send him. If not, please say so - it won't stop him reading your message, but it will save him time
trying to find you in the database.
Thanks for reading.
=====================================================================
From Chris Juden, as circulated:
=====================================================================
Dear correspondents
Thank you for your input and please find attached the revised CTC position paper on this
subject. This is now in final version and can be made public by whatever means may be at your
disposal. To effect change at this stage, a lot of cyclists will have to respond individually to
DfT and/or to their MP.
If you haven't already, please respond yourself, in your own words of course.
For a good example (only omitting the dynamo point[1]) I also suggest you look at:
<http://www.chapmancentral.com/Web/public.nsf/Documents/Road_Vehicle_Lighting_Regulations>
Chris Juden, CTC Technical Officer
[1] I fixed that
- guy
=====================================================================
And the content:
=====================================================================
ROAD VEHICLES LIGHTING REGULATIONS CTC Position Paper – 2nd edition following consultation –
2003.02.07 The proposal from DfT to allow flashing lamps on bicycles is most welcome, but only
addresses one issue, whereas there are several further ways in which the lighting regulations have
become out of touch with the means employed by careful cyclists to improve their conspicuity. This
is clear from the mere admission that "the use of flashing front and rear lights on pedal cycles is
becoming common". That was the situation 10 years ago. "Has become" and "ubiquitous" would be more
accurate now!
Red flashing lamps on breakdown vehicles etc.
---------------------------------------------
Before cycle lighting issues, DfT raise this other suggestion.
As mentioned above, red flashing lights are now so commonly used by cyclists as to now send one
clear message: BIKE. Their adoption by breakdown vehicles would dilute and confuse that message, so
we strongly oppose the appropriation of this, our unique marker, by any kind of motor vehicle.
It is not at all clear why breakdown vehicles need red flashing lights, when they are already
allowed to use yellow flashing lights. Note that the human eye is more responsive to yellow light
than to red. It is alleged (in the Background paragraph) that yellow beacons have may have lost
their effectiveness through inappropriate use. Are we to give the naughty child another toy to
replace the one he’s broken?
The need uniquely to identify such vehicles was mentioned. We respond with the need uniquely to
identify bicycles! However it is true that red flashing lights are also used by joggers and
equestrians. And cyclists don’t have a problem if this identifier becomes just a little less unique
by association with other vulnerable road users.
In their Regulatory Impact Assessment, DfT mentions the need to warn about breakdown personnel in
the road. We accept this point and consider it entirely appropriate for such personnel to wear red
flashing lights attached to their hi-vis clothing etc. We note and regret the number of persons
killed or injured on the hard shoulder or verges. Let people therefore directly identify and protect
themselves by wearing red flashing lights – not by hanging them on the vehicles they have vacated.
We therefore suggest an option A3: encourage people vacating or attending broken down vehicles to
wear red flashing lights.
Red and Blue flashers
---------------------
We agree that the conditions under which Police are allowed to use red flashing lights should be
more tightly controlled. Anything which keeps red flashing lights more clearly and uniquely
associated with vulnerable road users has to be a good thing.
B2 or B4 – flashers only?
-------------------------
Permission to use flashing lights in addition to approved, steady lights, option B2, probably needs
no further work from us to make it happen. But it is clear that most cyclists want to use flashers
only, at least at the rear, and as we cannot see an overwhelming reason why they shouldn’t, CTC
supports that desire.
The fears of some cyclists that flashing lights don’t pinpoint location and might not be so safe are
now known to be exaggerated. The cyclist’s main problem is to grab the motorist’s attention, which
flashing lights do best. After that any tracking issues become insignificant and are not in any
sense a real issue.
Option B4 is the only one that lets a flashing red LED be one's only rear lamp, so that’s the one we
must support. Unfortunately the DfT have muddied that option by lumping in a load of gimmicky
flashing pedal and wheel reflectors. Cyclists are not queuing up to add LEDs to their pedals and
wheels. Products like this have been around for as long as LED rearlamps but you do not see many on
bikes. DfT fears of a “profusion of flashing lamps” are unfounded. But if that’s a problem, we say
take them out of option B4.
The real problem for DfT and flashers only, is the lack of any equivalent to BS6102/3 for front and
rear lamps that allows DfT simply to say "okay if it passes that".
Some (not many) rear lamps which claim compliance with BS do also have a flashing mode, but there is
no testing regime in the BS to check the flash rate or the relative duration of the on/off phases.
Both these matters would have to be controlled before a flasher could be approved and neither are
likely to be added to the BS on a shorter timescale than this legislation.
Front flashers
--------------
Some (predominantly urban) cyclists also want to use only a flasher in front. So far as we know,
there are at present no white or near-white flashers that reach BS brightness levels. Anything less
than that will be a non-starter with DfT, so the issue is a little academic. However, such lamps are
possible and will certainly appear on the market very soon. It is hard to find any objection to
their exclusive use in situations where the general street lighting make any bike lamp redundant for
seeing the way. We envisage that riders may well wish to carry two front lights. Many do already,
conserving power by switching on the less economical main beam only where they need it. The flasher
becomes the cyclist’s dipped beam or sidelight.
Just as a pedal cycle does not have to be equipped with lights at all if it is used only in
daylight, it should not have to be equipped with a main beam headlight if used only in areas with
street lighting. And just as a motor vehicle may legally be driven anywhere with due caution on
dipped headlights (it does not even have to be fitted with main-beam headlights if its maximum speed
is limited to 25mph), so might a cycle be ridden anywhere with just a flashing front light – with
due caution.
Advice about the use of “main beam” and a flashing front lights on cycles can be most appropriately
given in the Highway Code. It will avoid unnecessary complication if RVLR simply allows front lights
to flash, just like rear ones. However, if DfT are moved to legislate on this matter it should be
noted that different regulations already apply to motor vehicles in the half hours of twilight
between sunset, official darkness and sunrise and under street lighting, that allow use of
sidelights only. So the mechanism and precedent exists to allow use of flashing front lamps on their
own, on pedal cycles, in equivalent situations.
The reasons to cut loose from BS
--------------------------------
A lot of design restrictions could be avoided by writing a few simple requirements into the
lighting regulations rather than 'calling up' an existing standard. That, however, would be seen by
DfT as a retrograde step. That's how the Regulations used to be, when they spoke about a "white"
front light "visible from a reasonable distance", before they got the BSI precisely to define the
colour and intensity in all directions. The trouble with precise definitions is they root you to a
point in history.
So, to be sure we were getting something equivalent to existing approved lamps, we could ask DfT to
extract just the most important criteria out of the BS, write them into RVLR and let the free market
take care of the rest. That, I am afraid, is the only quick way to make flashers legal as a
cyclist’s only lights. It could also solve some other problems.
Lights that are TOO good!
-------------------------
Increasing numbers of cyclists are resorting to very bright so-called off-road rechargeable
headlights in order to make themselves more conspicuous from the front. At present these are legal
as additions. However: when one has 30W of rechargeable twin halogen power on the handlebars, it is
ridiculous to add a comparatively puny approved headlamp and still shell out on disposable
batteries. For one thing there is seldom enough space left to mount a third lamp. So almost nobody
bothers and it really doesn't matter - except that it's illegal.
Why are these lamps not approved? There are various highly technical reasons to do with beam
pattern, the writing on the battery pack etc., none of which has much bearing on road safety. I'm
sure that they could be manufactured to BS, but we have to accept that Britain is a commercially
insignificant cycling country with peculiarly restrictive cycle lighting laws. Anything goes in the
USA and the southern half of Europe, so why should manufacturers bother? After all: they can sell it
in the UK just the same – it's only the users who may have a legal problem and few of them know it.
Fewer still policemen.
Without a European Directive on cycle lighting standards – and there's no prospect of that – foreign
lamp manufacturers (we no longer have any significant ones in Britain) will continue to say: "ah
yes, very nice standard, but I think my lamp will sell better if I make it like this". And it will!
Performance criteria
--------------------
Writing common minimum performance criteria for headlamps and rearlamps into the lighting
regulations is, I suggest, the way forward. BS6102/3 could still be mentioned as one of the ways to
ensure they are met.
DfT already propose to write some performance criteria into the regulations. Flashing additional
lights will be allowed between 1 and 4 flashes per second. For them to replace steady lights, we
should require that they at least deliver an equal intensity of light. For a rear lamp that would be
4cd and for a front lamp 400cd. For front lamps there should also be an upper limit and I’d suggest
the same as that applying to car headlamps: 24000cd.
Measuring becomes a bit technical for flashing lamps and I invite anyone who wants to know more to
look up the two physical laws mentioned below, which jointly provide an equitable means of assessing
the two permitted types of light, with regard to established behaviour of the human eye. Firstly it
must be noted that some apparently continuous lamps actually flash, faster than 10Hz, which must
also be allowed. Talbot’s law tells us to measure the continuous average output of those. According
to Blondel-Ray law, lamps that flash at 1 to 4Hz should be assessed by averaging the brilliance of
the flash over the duration of the flash phase plus 0.2 seconds.
BS6102 presently limits the light emitted 3.5° above beam centre to 70cd, presumably to stop
cyclists dazzling oncoming traffic. This is design restrictive (none of our high-power rechargeable
lamps control the beam this tightly) and ultimately futile, since the Lighting Regulations say
nothing about how the lamp is mounted on the bike. In any event the cyclist can quickly twist his
lamp to point wherever he wishes. No one, however, should need their lamp aimed higher than 1° below
the horizontal, and I suggest that writing that requirement into the Lighting regulations would be
more useful than the BS6102/3 limit.
It remains only to ensure that both these lights also direct some light to the sides. This is
easily done by defining zones within which the above averaged intensity must exceed certain levels,
e.g. 1cd everywhere 10° up and down and 45° R&L from the optical centre, and .05cd throughout 15°
U&D and 80° R&L.
Pedal Reflectors
----------------
It is most regrettable that DfT have ignored the problems experienced by cyclists using modern
clipless pedal systems. Most simply cannot have pedal reflectors, so cyclists wear reflective ankle
bands etc. It is all very well to talk about flashing lights on pedals and in the wheels, but it is
much more important to recognise alternative means of providing additional conspicuity in cases
where no such hardware can be applied. Nothing brings the law into greater disrepute than when
well-informed, law-abiding people find that it ignores their attempts to satisfy its intentions.
I believe that reflective ankle bands exist that can equal the performance of pedal reflectors.
Also, since the only function of front pedal reflectors is to take the place of rear ones when the
pedal rotates, front reflectors need only be fitted when a pedal is capable of being used either way
up. The regulations must be amended so that reasonable alternatives can be used. If necessary,
cyclists could add additional fixed reflectors (or an extra lamp) to the rear of the bicycle, but
alternatives of some sort must be allowed, not on the pedals.
It is not good enough to dismiss “keen” cyclists, the users of high-tech pedals, as an unimportant
minority. In many parts of Britain conditions are so hostile for cycling that, especially after
dark, such enthusiasts are almost the only cyclists out there.
Another important minority, growing in numbers, are the recumbent cyclists. On these machines the
pedal orientation is such that it is pointless to add reflectors even when this is possible, since
neither will be visible from in front and especially not from behind – not even if re-positioned.
Ankle bands will not work either in this orientation.
So an additional rear lamp or reflector appears the best solution for all concerned and will be
something that most cyclists could happily accept, since many already use more than one – provided
that any additional lamp may be a flasher.
Dynamo users when stationary
----------------------------
The existing law requiring an unlit cycle to be “kept to the left-hand or nearside edge of the
carriageway” seems quite reasonable until you consider the practicalities for dynamo users. There
you are, approaching a junction in the correct lane for going straight ahead, when the traffic
grinds to a halt. However the left-turn filter is still moving and fast. What to do? Stay put, which
is illegal since your lights are out, but perfectly safe because everything fore and aft has
likewise stopped? Or try to reach the kerb across that stream of traffic on your left! The latter
course is ridiculously hazardous and leads to even greater danger when a few minutes later you must
try to cross it again and re-enter the now accelerating stream of traffic recently vacated!
Modern dynamo systems are the most reliable of cycle lights and their use should be encouraged. We
suggest that clause 25 paragraph (9) item
(a), allowing a cyclist to be unlit whilst “waiting to proceed”, should be extended thus to cover
all circumstances where an approaching vehicle would also have to stop, even if the cyclist were
not there:
(b) a pedal cycle waiting to proceed provided–
(i) it is kept to the left-hand or nearside edge of the carriageway; or
(ii) it is waiting at a give-way or stop line and prevented from advancing by traffic signals or
vehicles crossing in front that have right-of-way; or
(iii) it is immediately behind another stationary vehicle
I should mention that dynamo rear lamps have been developed that stay on when you stop, albeit at
somewhat reduced brightness. A sensible compromise, that would encourage dynamo users to upgrade
their rear lamps, would be to allow the front light to be extinguished in all the above
circumstances, but still require at least 2cd output from the rear lamp (50% of the level normally
required).
Chris Juden, CTC Technical Officer
If you have any questions arising from the above or desire more information on any particular
points, please contact me at the CTC
Guy
===
** WARNING ** This posting may contain traces of irony. http://www.chapmancentral.com (BT ADSL and
dynamic DNS permitting)
NOTE: BT Openworld have now blocked port 25 (without notice), so old mail addresses may no longer
work. Apologies.
RVLR consultation.
Before you read it, a call to action: *please* respond to this consultation.
Why?
Because it matters. If sufficient people respond we might see an end to the stupid situation where
you can have a Cateye Stadium 3 on the front, a RealLite on the back, reflective jacket, cuff bands
and ankle bands, and still be breaking the law - but a 1980s Wonder Light, a .6W tungsten rear light
visible from 20 feet on a good day, wearing black from head to toe but with pedal reflectors, and
you're perfectly legal.
We are all of us I think responsible cyclists - we all (as far as I know) use lights and at least
think we're obeying the law - but the law is perverse and your lights, however good, may not be
legal. This might be because the writing on the battery is the wrong size! Even if you ride out with
a set of Lumicycles you're still not legal unless you carry a "BS Approved" (and functionally
worthless) front light. What does this mean in practice? It means those weasels at the insurance
companies can claim contributory negligence when some blind ****** knocks us off. It's happened
before and it'll happen again, unless we get the regs changed to recognise that functional lights
are what matters, not a standard which is irrelevant in any other country.
For the DfT page on the consultation, please see
<http://www.roads.dft.gov.uk/consult/lighting/index.htm>
You can respond, according to Informed Sources, by writing to your MP, writing to the DfT at the
address on their website, or by email to catharine.parton(at)dft.gsi.gov.uk [see, I've even tried to
help her avoid the spammers!]
I particularly recommend that you address in at least some detail any issues about which you feel
strongly or have particular knowledge - for example, the futility of pedal reflectors on 'bents, or
the regulations on dynamo lights which don't take into account standlights. My response is linked in
Chris'email below, so I must be doing something right!
Oh, and one last thing: Chris' documents all have a contact email address - chris.juden (at)
ctc.org.uk. If you are a CTC member, it's useful to enclose your membership number on any email you
send him. If not, please say so - it won't stop him reading your message, but it will save him time
trying to find you in the database.
Thanks for reading.
=====================================================================
From Chris Juden, as circulated:
=====================================================================
Dear correspondents
Thank you for your input and please find attached the revised CTC position paper on this
subject. This is now in final version and can be made public by whatever means may be at your
disposal. To effect change at this stage, a lot of cyclists will have to respond individually to
DfT and/or to their MP.
If you haven't already, please respond yourself, in your own words of course.
For a good example (only omitting the dynamo point[1]) I also suggest you look at:
<http://www.chapmancentral.com/Web/public.nsf/Documents/Road_Vehicle_Lighting_Regulations>
Chris Juden, CTC Technical Officer
[1] I fixed that
- guy=====================================================================
And the content:
=====================================================================
ROAD VEHICLES LIGHTING REGULATIONS CTC Position Paper – 2nd edition following consultation –
2003.02.07 The proposal from DfT to allow flashing lamps on bicycles is most welcome, but only
addresses one issue, whereas there are several further ways in which the lighting regulations have
become out of touch with the means employed by careful cyclists to improve their conspicuity. This
is clear from the mere admission that "the use of flashing front and rear lights on pedal cycles is
becoming common". That was the situation 10 years ago. "Has become" and "ubiquitous" would be more
accurate now!
Red flashing lamps on breakdown vehicles etc.
---------------------------------------------
Before cycle lighting issues, DfT raise this other suggestion.
As mentioned above, red flashing lights are now so commonly used by cyclists as to now send one
clear message: BIKE. Their adoption by breakdown vehicles would dilute and confuse that message, so
we strongly oppose the appropriation of this, our unique marker, by any kind of motor vehicle.
It is not at all clear why breakdown vehicles need red flashing lights, when they are already
allowed to use yellow flashing lights. Note that the human eye is more responsive to yellow light
than to red. It is alleged (in the Background paragraph) that yellow beacons have may have lost
their effectiveness through inappropriate use. Are we to give the naughty child another toy to
replace the one he’s broken?
The need uniquely to identify such vehicles was mentioned. We respond with the need uniquely to
identify bicycles! However it is true that red flashing lights are also used by joggers and
equestrians. And cyclists don’t have a problem if this identifier becomes just a little less unique
by association with other vulnerable road users.
In their Regulatory Impact Assessment, DfT mentions the need to warn about breakdown personnel in
the road. We accept this point and consider it entirely appropriate for such personnel to wear red
flashing lights attached to their hi-vis clothing etc. We note and regret the number of persons
killed or injured on the hard shoulder or verges. Let people therefore directly identify and protect
themselves by wearing red flashing lights – not by hanging them on the vehicles they have vacated.
We therefore suggest an option A3: encourage people vacating or attending broken down vehicles to
wear red flashing lights.
Red and Blue flashers
---------------------
We agree that the conditions under which Police are allowed to use red flashing lights should be
more tightly controlled. Anything which keeps red flashing lights more clearly and uniquely
associated with vulnerable road users has to be a good thing.
B2 or B4 – flashers only?
-------------------------
Permission to use flashing lights in addition to approved, steady lights, option B2, probably needs
no further work from us to make it happen. But it is clear that most cyclists want to use flashers
only, at least at the rear, and as we cannot see an overwhelming reason why they shouldn’t, CTC
supports that desire.
The fears of some cyclists that flashing lights don’t pinpoint location and might not be so safe are
now known to be exaggerated. The cyclist’s main problem is to grab the motorist’s attention, which
flashing lights do best. After that any tracking issues become insignificant and are not in any
sense a real issue.
Option B4 is the only one that lets a flashing red LED be one's only rear lamp, so that’s the one we
must support. Unfortunately the DfT have muddied that option by lumping in a load of gimmicky
flashing pedal and wheel reflectors. Cyclists are not queuing up to add LEDs to their pedals and
wheels. Products like this have been around for as long as LED rearlamps but you do not see many on
bikes. DfT fears of a “profusion of flashing lamps” are unfounded. But if that’s a problem, we say
take them out of option B4.
The real problem for DfT and flashers only, is the lack of any equivalent to BS6102/3 for front and
rear lamps that allows DfT simply to say "okay if it passes that".
Some (not many) rear lamps which claim compliance with BS do also have a flashing mode, but there is
no testing regime in the BS to check the flash rate or the relative duration of the on/off phases.
Both these matters would have to be controlled before a flasher could be approved and neither are
likely to be added to the BS on a shorter timescale than this legislation.
Front flashers
--------------
Some (predominantly urban) cyclists also want to use only a flasher in front. So far as we know,
there are at present no white or near-white flashers that reach BS brightness levels. Anything less
than that will be a non-starter with DfT, so the issue is a little academic. However, such lamps are
possible and will certainly appear on the market very soon. It is hard to find any objection to
their exclusive use in situations where the general street lighting make any bike lamp redundant for
seeing the way. We envisage that riders may well wish to carry two front lights. Many do already,
conserving power by switching on the less economical main beam only where they need it. The flasher
becomes the cyclist’s dipped beam or sidelight.
Just as a pedal cycle does not have to be equipped with lights at all if it is used only in
daylight, it should not have to be equipped with a main beam headlight if used only in areas with
street lighting. And just as a motor vehicle may legally be driven anywhere with due caution on
dipped headlights (it does not even have to be fitted with main-beam headlights if its maximum speed
is limited to 25mph), so might a cycle be ridden anywhere with just a flashing front light – with
due caution.
Advice about the use of “main beam” and a flashing front lights on cycles can be most appropriately
given in the Highway Code. It will avoid unnecessary complication if RVLR simply allows front lights
to flash, just like rear ones. However, if DfT are moved to legislate on this matter it should be
noted that different regulations already apply to motor vehicles in the half hours of twilight
between sunset, official darkness and sunrise and under street lighting, that allow use of
sidelights only. So the mechanism and precedent exists to allow use of flashing front lamps on their
own, on pedal cycles, in equivalent situations.
The reasons to cut loose from BS
--------------------------------
A lot of design restrictions could be avoided by writing a few simple requirements into the
lighting regulations rather than 'calling up' an existing standard. That, however, would be seen by
DfT as a retrograde step. That's how the Regulations used to be, when they spoke about a "white"
front light "visible from a reasonable distance", before they got the BSI precisely to define the
colour and intensity in all directions. The trouble with precise definitions is they root you to a
point in history.
So, to be sure we were getting something equivalent to existing approved lamps, we could ask DfT to
extract just the most important criteria out of the BS, write them into RVLR and let the free market
take care of the rest. That, I am afraid, is the only quick way to make flashers legal as a
cyclist’s only lights. It could also solve some other problems.
Lights that are TOO good!
-------------------------
Increasing numbers of cyclists are resorting to very bright so-called off-road rechargeable
headlights in order to make themselves more conspicuous from the front. At present these are legal
as additions. However: when one has 30W of rechargeable twin halogen power on the handlebars, it is
ridiculous to add a comparatively puny approved headlamp and still shell out on disposable
batteries. For one thing there is seldom enough space left to mount a third lamp. So almost nobody
bothers and it really doesn't matter - except that it's illegal.
Why are these lamps not approved? There are various highly technical reasons to do with beam
pattern, the writing on the battery pack etc., none of which has much bearing on road safety. I'm
sure that they could be manufactured to BS, but we have to accept that Britain is a commercially
insignificant cycling country with peculiarly restrictive cycle lighting laws. Anything goes in the
USA and the southern half of Europe, so why should manufacturers bother? After all: they can sell it
in the UK just the same – it's only the users who may have a legal problem and few of them know it.
Fewer still policemen.
Without a European Directive on cycle lighting standards – and there's no prospect of that – foreign
lamp manufacturers (we no longer have any significant ones in Britain) will continue to say: "ah
yes, very nice standard, but I think my lamp will sell better if I make it like this". And it will!
Performance criteria
--------------------
Writing common minimum performance criteria for headlamps and rearlamps into the lighting
regulations is, I suggest, the way forward. BS6102/3 could still be mentioned as one of the ways to
ensure they are met.
DfT already propose to write some performance criteria into the regulations. Flashing additional
lights will be allowed between 1 and 4 flashes per second. For them to replace steady lights, we
should require that they at least deliver an equal intensity of light. For a rear lamp that would be
4cd and for a front lamp 400cd. For front lamps there should also be an upper limit and I’d suggest
the same as that applying to car headlamps: 24000cd.
Measuring becomes a bit technical for flashing lamps and I invite anyone who wants to know more to
look up the two physical laws mentioned below, which jointly provide an equitable means of assessing
the two permitted types of light, with regard to established behaviour of the human eye. Firstly it
must be noted that some apparently continuous lamps actually flash, faster than 10Hz, which must
also be allowed. Talbot’s law tells us to measure the continuous average output of those. According
to Blondel-Ray law, lamps that flash at 1 to 4Hz should be assessed by averaging the brilliance of
the flash over the duration of the flash phase plus 0.2 seconds.
BS6102 presently limits the light emitted 3.5° above beam centre to 70cd, presumably to stop
cyclists dazzling oncoming traffic. This is design restrictive (none of our high-power rechargeable
lamps control the beam this tightly) and ultimately futile, since the Lighting Regulations say
nothing about how the lamp is mounted on the bike. In any event the cyclist can quickly twist his
lamp to point wherever he wishes. No one, however, should need their lamp aimed higher than 1° below
the horizontal, and I suggest that writing that requirement into the Lighting regulations would be
more useful than the BS6102/3 limit.
It remains only to ensure that both these lights also direct some light to the sides. This is
easily done by defining zones within which the above averaged intensity must exceed certain levels,
e.g. 1cd everywhere 10° up and down and 45° R&L from the optical centre, and .05cd throughout 15°
U&D and 80° R&L.
Pedal Reflectors
----------------
It is most regrettable that DfT have ignored the problems experienced by cyclists using modern
clipless pedal systems. Most simply cannot have pedal reflectors, so cyclists wear reflective ankle
bands etc. It is all very well to talk about flashing lights on pedals and in the wheels, but it is
much more important to recognise alternative means of providing additional conspicuity in cases
where no such hardware can be applied. Nothing brings the law into greater disrepute than when
well-informed, law-abiding people find that it ignores their attempts to satisfy its intentions.
I believe that reflective ankle bands exist that can equal the performance of pedal reflectors.
Also, since the only function of front pedal reflectors is to take the place of rear ones when the
pedal rotates, front reflectors need only be fitted when a pedal is capable of being used either way
up. The regulations must be amended so that reasonable alternatives can be used. If necessary,
cyclists could add additional fixed reflectors (or an extra lamp) to the rear of the bicycle, but
alternatives of some sort must be allowed, not on the pedals.
It is not good enough to dismiss “keen” cyclists, the users of high-tech pedals, as an unimportant
minority. In many parts of Britain conditions are so hostile for cycling that, especially after
dark, such enthusiasts are almost the only cyclists out there.
Another important minority, growing in numbers, are the recumbent cyclists. On these machines the
pedal orientation is such that it is pointless to add reflectors even when this is possible, since
neither will be visible from in front and especially not from behind – not even if re-positioned.
Ankle bands will not work either in this orientation.
So an additional rear lamp or reflector appears the best solution for all concerned and will be
something that most cyclists could happily accept, since many already use more than one – provided
that any additional lamp may be a flasher.
Dynamo users when stationary
----------------------------
The existing law requiring an unlit cycle to be “kept to the left-hand or nearside edge of the
carriageway” seems quite reasonable until you consider the practicalities for dynamo users. There
you are, approaching a junction in the correct lane for going straight ahead, when the traffic
grinds to a halt. However the left-turn filter is still moving and fast. What to do? Stay put, which
is illegal since your lights are out, but perfectly safe because everything fore and aft has
likewise stopped? Or try to reach the kerb across that stream of traffic on your left! The latter
course is ridiculously hazardous and leads to even greater danger when a few minutes later you must
try to cross it again and re-enter the now accelerating stream of traffic recently vacated!
Modern dynamo systems are the most reliable of cycle lights and their use should be encouraged. We
suggest that clause 25 paragraph (9) item
(a), allowing a cyclist to be unlit whilst “waiting to proceed”, should be extended thus to cover
all circumstances where an approaching vehicle would also have to stop, even if the cyclist were
not there:
(b) a pedal cycle waiting to proceed provided–
(i) it is kept to the left-hand or nearside edge of the carriageway; or
(ii) it is waiting at a give-way or stop line and prevented from advancing by traffic signals or
vehicles crossing in front that have right-of-way; or
(iii) it is immediately behind another stationary vehicle
I should mention that dynamo rear lamps have been developed that stay on when you stop, albeit at
somewhat reduced brightness. A sensible compromise, that would encourage dynamo users to upgrade
their rear lamps, would be to allow the front light to be extinguished in all the above
circumstances, but still require at least 2cd output from the rear lamp (50% of the level normally
required).
Chris Juden, CTC Technical Officer
If you have any questions arising from the above or desire more information on any particular
points, please contact me at the CTC
Guy
===
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