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Topic Title: Car headlamps
Topic Summary: Does bigger mean less dazzle?
Created On: 07 December 2006 04:26 PM
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 24 November 2009 11:59 PM
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amezcua

Posts: 17
Joined: 11 November 2009

OK here is the solution to headlamp glare which does not rely on other drivers.
On the inside of the screen place a layer of clear polaroid film.
If you wear a pair of clear glass specs the view would be unchanged.Next apply a diagonal film of clear polarioid to the specs so that the view through the screen will show the road "perspective "matching the angle of polaroid film on the specs.
Providing the angular relation of the two polaroid films match you then have a cheap effective way to dim the glare .
To understand the comments about road perspective just look at any u tube film showing a car on a motorway (or freeway). The centre of the road makes an angle of about 40 degrees to the horizontal.If you cut away the top of this "screen" at a further angle of 30 degrees (this is the point of the triangle where distant cars will appear on the screen),you will be able to control nearly all the glare by very small head movements.
Sheets of polaroid film can be bought for just a few pounds (or dollars).
Sorted.
 25 November 2009 09:47 AM
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amezcua

Posts: 17
Joined: 11 November 2009

To complete the story we have to provide something for motorcyclists.
If the visor has a layer of polaroid film inside it then all we need is the polaroid adjusted specs to give a glare free ride. You`ll get used to it.
 27 November 2009 10:37 PM
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mikemolano

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thanks good information publicidad en internetpublicidad en internet

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 29 November 2009 09:00 PM
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andy6

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I believe there is some legislation for the position of headlamps on vehicles. As in, they have to be a certain distance from the floor and a certain distance apart so that in low visibility you can geuss its size.
For example a cars headlamps have a certain standard postition, where a truck has another.
 29 November 2009 09:26 PM
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amezcua

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Andy6 If you guess right do you win a prize?------Did the polaroid film idea make sense to you?
Most people have heard of polaroid and imagine a brown tinged pair of sunglasses.Have you ever seen a sheet of clear polaroid film? This is a one man survey.You`re about to make history.Think carefully now.
 28 December 2009 11:05 AM
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Paul1966

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Joined: 21 December 2004

Originally posted by: andy6
I believe there is some legislation for the position of headlamps on vehicles. As in, they have to be a certain distance from the floor and a certain distance apart


Yes, the Road Vehicles Lighting Regulations 1989 specify limits on the position of headlamps. For all late-model cars the low beams must be located no more than 400mm from the edge of the vehicle and at a height of between 500 and 1200mm. Where separate high-beam lamps are used, they must not be located outboard of the low beams.

Schedules 4 & 5 give the full details, and the dates from which each of the requirements became operative:

http://www.opsi.gov.uk/si/si1989/Uksi_19891796_en_1.htm
 19 January 2010 08:43 PM
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fsmith

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When I was a young man optics was an art (at least car optics) and headlights had a very soft beam and therefore you went from low light output to high light output over a larger angle. As the optics have got better the cut-off has become much sharper and whilst this has improved the light levels and evenness in the beam it has also made the out of beam darker.

When the transition was softer your eyes had a little longer to adapt as the light level went up and down thus the lights did not seem to flash so much.

Personally I think driving behind the older lights was safer, if harder work, but that's progress.

.... and no I am not an old man, just middle aged!
 20 January 2010 10:48 AM
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amillar

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I followed a new Audi A6 last night with (I assume) LED stop tail lamps arranged in two large rings. When in 'stop' it was absolutely dazzling, so much so that I had to stop some distance away. (And this wasn't in the dark, it was around sunset.) I do wonder whether the legislation is keeping up with the technology?

-------------------------
Andy Millar CEng MIET CMgr MCMI

http://www.linkedin.com/in/millarandy

"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert
 23 January 2010 10:37 AM
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Paul1966

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Personally, I think people are getting carried away with ever-brighter vehicle lighting, both in terms of what's fitted and the way it's used.

Yes, we need adequate lights to see and be seen, but we don't need high beams which are so intense they can dazzle somebody a half mile away, and we don't need headlights and even fog lights switched on the moment the sun goes behind a cloud, as a lot of people now seem to do.

Remember when it was common practice on well-lit city streets to drive on just sidelights? You rarely see that today, even though it's still perfectly legal to do so. We just seem to be adding to overall blaze and glare of lights.

There have been various calls to mandate daytime running lights too, as are already common in some European countries and Canada. It's more unnecessary glare which serves no useful purpose in broad daylight, but can actually mask more vulnerable road users such as bicyclists and pedestrians.
 29 January 2010 11:29 PM
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amezcua

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Paul 1966 Exactly right.Just what I think. I realised today how strange it is that the original polaroid anti dazzle was thought of so long ago.How dim would those lights have been? The possible alternative would be some system to light your own vehicle.I once saw a car with a green neon light system underneath it lighting the road surface.Very effective. I would prefer the body to be lit .Then the low tech reflective plastic could be used and the frequent sight of cars with lights not working at all, would not be such a worry.
How can headlamp designers be so ignorant of the effect these powerful lights have on other drivers? It shows remarkable lack of intelligence.
 04 February 2010 09:36 AM
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dasy2k1

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Originally posted by: amillar

I followed a new Audi A6 last night with (I assume) LED stop tail lamps arranged in two large rings. When in 'stop' it was absolutely dazzling, so much so that I had to stop some distance away. (And this wasn't in the dark, it was around sunset.) I do wonder whether the legislation is keeping up with the technology?


quite possibly not,
the RVLR specify 5w for a rear marker light and 55w for a brake light,
now if you had the full 55w in a ring of 2.5w Luxieon stars...... well im guessing that would cause a fair amount of dazzle
 04 February 2010 10:56 AM
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Paul1966

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Originally posted by: dasy2k1
the RVLR specify 5w for a rear marker light and 55w for a brake light,


For post-1971 vehicles brake lights are required to be between 15 and 36 watts each. See schedule 12 of the RVLR 1989, part I, section 8:

http://www.opsi.gov.uk/si/si19...1796_en_17.htm#nsch12

However, beyond the mandatory two brake lights, there's no specific limit on the number of additional brake lights which may be fitted, each of which may be 15 to 36W.

How would you count lights made up of multiple LED's though? Each individual LED can't be counted (legally) as a separate lamp, otherwise it wouldn't meet the 15W minimum. So is the entire cluster a single lamp, and thus limited to 36 watts?

So much of the "dazzle factor" depends upon the overall design of the fitting though. My old '79 Chrysler had dual brake/turn signal lights each side using the standard #1157 dual-filament lamps, with each segment of the red lens being about 4 inches square. The brake lights were certainly noticeable, but being well diffused they certainly would not be dazzling, even when sitting directly behind them, despite there being around 100W total across both sides.

Put the same amount of power into lights which focus the beam more, and the result could be quite different.
 10 February 2010 08:07 AM
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mojojo12

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Joined: 10 February 2010

I am not sure if there is direct relation with the size of the car headlamps to the dazzle. However, I believe that one of the major contributing factors is the material used.
 16 March 2011 02:15 AM
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susanavilon

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Joined: 16 March 2011

I just want to share this also about the sidelights..
When we hear the term 'sidelights', most drivers will automatically think of the small / dim lights on the front of the vehicle.However, this term also includes the rear number plate light. In some cars, these lights come on automatically when the engine is switched on.It is true to say that sidelights are of limited use when compared with headlights, particularly in winter weather conditions. However, there are certain times where their use is vitally important. Sidelights must be switched on between sunset and sunrise even in brightly lit areas as they will help other road users to see your vehicle. If you have a dark coloured car, you may consider switching on these lights earlier. I hope this could help you.

Edited: 16 March 2011 at 02:47 AM by susanavilon
IET » Transport engineering » Car headlamps

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