Defective cars?

General cycling advice ( NOT technical ! )
SA_SA_SA
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Re: Defective cars?

Postby SA_SA_SA » 24 Nov 2015, 9:03pm

Brucey wrote:......
Current EU rules for lighting permit (in fact encourage) as sharp a cutoff of the dipped beam as possible, and if it isn't aimed a long way up the road, you car will fail the MOT! It is as if bumpy/undulating roads don't exist in 'Lighting Regulation World'. Even if the lights are set correctly (which they are often not) oncoming traffic is often blinded by what are effectively bright flashing lights from oncoming traffic on such roads. I don't think that it is terribly difficult to see that this does not in any way improve road safety! astonishing is going on????
....

But haven't (UN-)ECE lamps always had a sharp cutoff? That is the difference between them and US SAE lamps which seem to be regarded as more dazzling by allowing 2000cd per lamp above the horizon vs 625cd for a non filament UN-ECE lamp (filament ones are allowed 437cd, but are brighter in practice due to the higher alternator voltage vs test voltage :shock: ). Isn't the required degree of dip (the 1.3% plate on most cars) to take care of undulating roads? So if cars now cause trouble is that not because their dipped headlamps aren't dipped enough to be legal? Someone suggested speed bumps were knocking them out of adjustment now.

Did manufacturers in the past just angle lamps down more than they could have?

I would rather deal with short blips of dazzle (which may be predictable: eg due to speed bumps) than be constantly dazzled.


I remember reading that the cutoff in the prototype ECE rules for HID lamps was to be much sharper than for halogen, but that testers disliked it because they got no warning of a pending increase in brightness when a car when over bump: the brightness just went from a kitten to lion with no warning, so the standard abandoned that idea.

I agree some new modern rules seem stupid / unfair: why ban selective yellow headlamps but allow disagreeable cold blue-white ones?

Brucey wrote:.....Another gripe is car indicator lights; again they are now designed not with common sense, but to a bad set of rules. 25 years ago an indicator lamp would be designed with a prismatic outer face, amber in colour. Such lamps are clearly visible from all angles even in bright sunlight and furthermore you would easily know where to look for a flashing indicator light on the vehicle. Modern lights mostly have clear lenses and are NOT clearly visible over such a wide range of angles (or in bright sunlight) and in addition it is not clear where even to look on any given vehicle for such a signal. I am pretty sure that whoever designed the rules did so for the benefit of other motorists (an failed there too BTW) but they certainly never thought that the most vulnerable road users need to be able to see these lights at funny angles if they are to stay alive. If you have just been squashed by a left-turning car, it is scant consolation that 'they were in the wrong'....

I agree that clear filament indicators are usually rubbish in the sun (and relying on orange bulbs is a stupid idea that lets people fit the wrong clear bulb) but I wonder if the standard actually changed: computer designed reflectors may have made it possible to ditch the amber diffuser and styling won over functionality. However, it seems a pity the standard has not been updated to require the useful properties so easily provided by an amber diffuser and put poncy design/marketing persons in their place.... :)
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Brucey
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Re: Defective cars?

Postby Brucey » 24 Nov 2015, 9:42pm

I think that whilst the regulations may have said 'you can have XYZ' in the past, the reality was that such things could not easily be manufactured, thus headlights always had cutoffs that were less abrupt -and somewhat more forgiving- than the standard allowed for.

On the whole the 'above horizon brightness' is not a big problem except in those cases where all the light comes from a small part of a small reflector; in these cases the capacity to dazzle oncomers is considerably more than it needs to be. Many modern cars have naked LED running lights and these have a source brightness that is excessive IMHO; again this can dazzle oncomers quite needlessly.

These days light sources are more compact and reflectors can be better designed and manufactured. This allows lighting designers to meet or exceed the most extreme cutoff cases allowed under the regulations, which basically wasn't possible previously. [When the lamp dazzles, it does so worse than before, because the source brightness -from a small reflector- is nearly always higher even for the same illumination value on the subject.] Plenty of dipped beams now have the very brightest part of the beam just below the cutoff. The argument is that you need this because this is the part of the beam that reaches furthest and meets the road at the most glancing of angles.

This view is mistaken in that objects that you need to see are not lying at the same angle as the road surface, and ignores the fact that both road surfaces and vehicle suspensions cause the alignment of the headlights to pitch by far more than ~1.2 degrees. Thus the 'benefit' to the driver of the car with those lights is slight, and the disadvantage to oncoming drivers is considerably greater than that.

If a vehicle has a 2.5m wheelbase (which is unrealistically long for a typical car), it just needs one axle to rise or drop 30mm more than the other and the vehicle will pitch 1.2 degrees. An average car might need nearer 25mm axle/road movement to produce a similar pitch. This kind of thing is going to happen all the time, so even if the headlights are set correctly, modern lights will inevitably dazzle oncomers for several reasons.

The whole arrangement is just daft, very poorly thought out IMHO. With just a little more effort, modern lights could offer benefits to all road users without the harmful effects of dazzle.

cheers
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pete75
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Re: Defective cars?

Postby pete75 » 24 Nov 2015, 10:24pm

Many modern cars use LEDs not bulbs and also have adaptive lighting systems which sense the presence of other vehicles on the road and adjust the lighting pattern accordingly so as not to dazzle.

Brucey
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Re: Defective cars?

Postby Brucey » 24 Nov 2015, 11:01pm

pete75 wrote:Many modern cars use LEDs not bulbs and also have adaptive lighting systems which sense the presence of other vehicles on the road and adjust the lighting pattern accordingly so as not to dazzle.


maybe, but I doubt that they are much benefit to cyclists and I also doubt that they account for the car or the road pitching a few degrees, either.

I'd love for my doubts to be disproven BTW... it'd be nice to see some 'real progress' for a change.... :wink:

cheers
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SA_SA_SA
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Re: Defective cars?

Postby SA_SA_SA » 24 Nov 2015, 11:25pm

But they seemed to step back from requiring a sharper cutoff when developing the electronic headlamp standard, it would then seem remiss of them not to then forbid too sharp a cutoff in the final standard?

Do you notice the problem more with modern halogen headlamps or modern electronic lightsource headlamps?

I often notice extra dazzle from one headlamp only hence assumed the problem was from misaligned headlamps.

2.5in Projector headlamps (of same shade) can be dazzling or not, so I presumed dazzle was simply alignment problems.

Out of curiosity at what angle do you think dipped headlamps (at usual car height) should be dipped down (and hence what range of road illumination do you expect (and thus at what speed do you expect to drive at in order to still be able to avoid unlit pedestrians etc).


I thought DRLs are meant to be switched off when other lights are on: I presume the fitted ones that do (seems to be the nicer lightguide ones) are dimmed to count as side lights. Ones that are not are perhaps incorrect owner retrofits: I saw some left on a Landrover which looked like an afterthought.

When driving I always thought dipped beams had a terrible range for the speeds most people drive at: more than 30mph seemed to risk unlit pedestrians etc but that doesn't stop anyone going faster. MotorVehicles with only dipped lamps are limited to 25mph...perhaps not a coincidence?

I have wondered if clear lens headlamps with CAD reflectors are actually superior to fresnel lensed ones or if it is just a styling choice with clear lens CAD reflector able to get through the standard even though a similarly carefully designed CAD/plain reflector with fresnel lens might be more pleasant.

The American envy of the ECE standards lower dazzle due to the sharp cutoff and lower above horizon value seems to date from the days of fresnel halogen lamps ....

Brucey wrote:..... Plenty of dipped beams now have the very brightest part of the beam just below the cutoff.

Isn't that the definition of a cutoff or am I missing something :? ?
The argument is that you need this because this is the part of the beam that reaches furthest and meets the road at the most glancing of angles.
This view is mistaken in that objects that you need to see are not lying at the same angle as the road surface, and ignores the fact that both road surfaces and vehicle suspensions cause the alignment of the headlights to pitch by far more than ~1.2 degrees. Thus the 'benefit' to the driver of the car with those lights is slight, and the disadvantage to oncoming drivers is considerably greater than that.

does that mean that the old lamps you think had a gentler cutoff are the same dazzle as what you view as a modern sharp cutoff which is dipped more?

I thought ECE headlamps were meant to be able to be adjusted by setting the bright to less bright visible border on a wall:
Has the official garage headlamp setting method changed rather the headlamps?

https://www.unece.org/fileadmin/DAM/tra ... 67-27e.pdf

http://www.unece.org/fileadmin/DAM/tran ... 48r12e.pdf
Annex 6: aim set by bright to dim cutoff line not 437cd/625cd line?
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Brucey
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Re: Defective cars?

Postby Brucey » 25 Nov 2015, 1:21am

SA_SA_SA wrote:
Brucey wrote:..... Plenty of dipped beams now have the very brightest part of the beam just below the cutoff.

Isn't that the definition of a cutoff or am I missing something :? ?


some headlights have a consistent brightness below the cutoff and the cutoff ltself is not too abrupt. Others have x2 or x3 the average brightness in a narrow band just below the cutoff; these have a far greater capacity to dazzle.

When driving above 40-50mph on dipped beam you are basically in the realms of swerving round unlit objects in the road rather than stopping for them, if you only see them when they fall within the spread of the dipped beam. In this respect it doesn't matter if the lights are dipped to 1.3 degrees or 1.5 or whatever; if you wanted to be able to stop in time you'd be driving a lot slower than that anyway.

Note also that providing more light within the dipped beam may even be counterproductive; eyes work on contrast ratios, and if you make more light in the illuminated region, you lessen your chances of seeing anything dimly lit outside of that region. This is also why dazzle from oncoming vehicles is so damaging, and why it is that the interior illumination in cars shouldn't be turned up either.

If you do some sums you can get an idea of how bad things are; an 'old' headlight design (say a 6" round with with a mushy cutoff) might illuminate (dazzle) oncomers with about half the full dip beam intensity should the car pitch about two degrees. But a modern might have

a) twice the average brightness in the dip beam
b) two or three times the average brightness just below the cutoff
c) a reflector half the size, making the source brightness ~x4 for any given amount of illumination.

By my reckoning that is up to ~x24 the capacity to dazzle oncomers; can this really be a good idea?

cheers
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[XAP]Bob
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Re: Defective cars?

Postby [XAP]Bob » 25 Nov 2015, 8:13am

Of course it's a good idea - it looks cool.


:evil:
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
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mrjemm
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Re: Defective cars?

Postby mrjemm » 25 Nov 2015, 11:19am

Oooh, dazzly headlights are a horrible thing. :evil:

Last night I drove to Blackpool and back in the dark and occasionally heavy rain, and I was getting maddened by all the poorly aligned (squinting) headlights, headlights being left on full beam, HID (?) beams that are generally too bright, even dipped, and the same that are simply not capable of compensating for vehicle motion/road topography. We were in a teeny Panda, but they're quite upright, and I get the same in my Berlingo, in that some bigger cars, notably 4x4/SUV style vehicles, are that much higher, and so their headlights are higher, which of course means they are more prone to dazzling also, even when dipped, but the drivers of this style of car are often of the type that don't care about other road users (obviously) and simply don't bother dipping.

But...

As a pedallist, I am also sick of the inconsiderate amongst us. Yes, the self-centered, selfish, smug, truly inconsiderate pedalling persons who have ridiculously bright lights. The Lancaster Canal is particlarly full of the gits at commuting home time, with their intensely powerful lights dazzling ahead of them, and so often, as I pedal in to meet Mme, I get my retinae burned out by these twonks who refuse to adjust the angle their light-sabres are pointing, or use a lower setting, and subsequently find myself risking a chilly dunk in the murky muck of the canal through temporary blindness, my blind rage being entirely separate to this. :evil: :evil:

So, really, this whole subject is down to lack of consideration, and the usual "I'm alright Jack" nature of folk, be they drivers or cyclists. As a driver and a cyclist and a pedestrian, I feel guilt for being yet another human, and in no capacity can I feel to be part of a group that is any better than the other in this regard. So, as cyclists, we should all stop whinging about car users unless we accept that there are those amongst us just as bad, after all, most of us also drive, so if you're happy to dazzle on a bike, are you any better in a car?

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mjr
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Re: Defective cars?

Postby mjr » 25 Nov 2015, 12:07pm

mrjemm wrote:So, as cyclists, we should all stop whinging about car users unless we accept that there are those amongst us just as bad, after all, most of us also drive, so if you're happy to dazzle on a bike, are you any better in a car?

No, we shouldn't stop pushing for motorists to stop being anti-social/illegal just because some cyclists do. Two wrongs don't make a right! There are more motorists than cyclists and the damage they do is far greater.

I can't answer the second bit because I'm not happy to dazzle on a bike. :)
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mrjemm
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Re: Defective cars?

Postby mrjemm » 25 Nov 2015, 12:15pm

mjr wrote:
mrjemm wrote:So, as cyclists, we should all stop whinging about car users unless we accept that there are those amongst us just as bad, after all, most of us also drive, so if you're happy to dazzle on a bike, are you any better in a car?

No, we shouldn't stop pushing for motorists to stop being anti-social/illegal just because some cyclists do. Two wrongs don't make a right! There are more motorists than cyclists and the damage they do is far greater.

I can't answer the second bit because I'm not happy to dazzle on a bike. :)


OK, I agree that 2 wrongs don't make a right, and we should indeed keep moaning about cars, but we must not forget there are those amongst us who are also selfish, inconsiderate twonks. It's a human thing to be crap, not a motorist or otherwise. :x

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mjr
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Re: Defective cars?

Postby mjr » 25 Nov 2015, 1:21pm

We're never allowed to forget that there are crap cyclists, are we? Almost every media discussion about cycling contains a naughty-cyclist element.
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SA_SA_SA
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Re: Defective cars?

Postby SA_SA_SA » 25 Nov 2015, 1:48pm

Brucey said: '..... Plenty of dipped beams now have the very brightest part of the beam just below the cutoff....'
SA_SA_SA replyed: 'Isn't that the definition of a cutoff or am I missing something :? ?'

Brucey replyed: 'some headlights have a consistent brightness below the cutoff and the cutoff ltself is not too abrupt. Others have x2 or x3 the average brightness in a narrow band just below the cutoff; these have a far greater capacity to dazzle.
'
Oh dear I have confused matters/myself because I think I have used the term cutoff to mean 2 different things because there are two cutoffs: the extreme one between the brightest part of dipped see-ing beam and the intermediate area (I shall now call this the lower cutoff) and the one between the intermediate area and the above horizon max of 625cd(or whatever is appropriate to lamp kind) which I shall call the upper cutoff . When thinking headlamp aim (eg when viewing headlamp cutoff on wall I am thinking of the lower cutoff.

The first document I quoted seems to allow so much latitude in adjustment that I think the upper cutoff could be allowed to point upwards above horizontal. I suppose I am now going to read said ECE reg 48 etc to see whether manual aiming is based on the upper cutoff not the lower as I thought. Anyone have any pointers?

ECE headlamps seem to expect some manual adjustment to occur due to the fitting of a level adjuster on the dash for when using heavy loads and the lower cutoff (viewed on a wall) would seem the obvious thing to check. If the upper cutoff is used only a machine could be used to adjust headlamps.

When driving above 40-50mph on dipped beam you are basically in the realms of swerving round unlit objects in the road rather than stopping for them, if you only see them when they fall within the spread of the dipped beam. In this respect it doesn't matter if the lights are dipped to 1.3 degrees or 1.5 or whatever; if you wanted to be able to stop in time you'd be driving a lot slower than that anyway.

Thats what I felt :).

NB I find I do dislike 2in projector dipped lamps (rather than the usual 2.5in) (on a bus: why, what does a flat fronted bus need tiny headlamps for? :( )

So far I still don't think a non-mushy cutoff transition is a standards bodies idea but thoughtless/careless/stupid implementation by lamp manufacturers. Of course the standard should respond by tightening the standard. But aiming by reference to lower cutoff makes more sense to me, assuming the angle covered by intermediate area is then fixed to suit the worst case allowed aim.
Why would they reject a less mushy cutoff for electronic lamps but not for halogen?

Do you have links to any UN-ECE documents that state this as a new policy?
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Brucey
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Re: Defective cars?

Postby Brucey » 25 Nov 2015, 5:04pm

SA_SA_SA wrote: .....So far I still don't think a non-mushy cutoff transition is a standards bodies idea but thoughtless/careless/stupid implementation by lamp manufacturers....


I have always assumed that the standard allowed an abrupt transition because at one time it was difficult to implement this. I think that if you give lamp designers a poorly defined task (to make the lamps 'as good as possible' for the 'user') and then don't constrain the end result correctly, you end up where we are.

I don't know the answers to all your questions BTW.

cheers
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SA_SA_SA
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Re: Defective cars?

Postby SA_SA_SA » 26 Nov 2015, 4:08pm

Brucey wrote:I don't know the answers to all your questions BTW.
...

Thats OK.
:)
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mrjemm
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Re: Defective cars?

Postby mrjemm » 26 Nov 2015, 6:34pm

mjr wrote:We're never allowed to forget that there are crap cyclists, are we? Almost every media discussion about cycling contains a naughty-cyclist element.


True, but this is a cycling forum, and to bitch about motorists all the time is fine, but there's an element of hypocrisy if we don't keep our own house in order. This isn't POBs on BSOs (oh, how dare he use those mean TLAs? The shame, diddums) I'm on about, but well kitted commuting types for one example. And there've been plenty on here in the past going on about their super dooper mega cree blasters.

Yeah yeah there are naughty motoids, but there are those amongst us who should realise they're not all holier than thou.