Looked in my mirror the other evening on the M4 and noticed that the sidelights on one of the cars behind me appeared to be 'bouncing' (not vibrating) up and down. The main lights looked normal - not moving at all. As the car came passed, I noticed it was an Insignia.
A few miles further on, the same thing happened again, and again it was an Insignia.
Unless there's a sidelights on springs option for this car, presumably it's some sort of interaction between the mirror and light, but I can't understand exactly what causes it.
Anybody else seen this, and/or know what's going on?
You can just about make out the sidelights in this picture
www.businesscar.co.uk/story_attachment.asp?storycode=2837&seq=2&type=P&c=1
right at the outside top corners of the light units, in a sort of V-on-its-side shape.
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Those aren't sidelights they are DRLs. They are often very focused, and very high intensity. I suspect that the movement was an illusion caused by the pitching of the car causing your viewpoint to be alternately on and off axis.
The distractions of these abominations and the nodding xenons are a change for the worse in my opinion.
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>> The distractions of these abominations and the nodding xenons are a change for the worse
Couldn't agree more, the edge of the xenon beam as the car dips looks momentarily looks like the slight flash of blue of an approaching emergency vehicle.
I'm quite surprised that grown ups would want some of the more bling DRL's.
Odd isn't it these unnecessary lights are getting brighter, just as indicators both front and rear behind reflectors or inside headlight units and LED flashers and brake lights in the late summer sun virtually disappear.
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The complaints about Xenons may not die out as the complaints did when halogen ("that irritating white light") was adopted in the 60s.
It's because older drivers are susceptible to glare from Xenons "because of their increased intraocular light scattering, glare sensitivity, and photostress recovery time." www.ncbi.nlm.nih.gov/pmc/articles/PMC1771460/
Interesting stuff. The older you get, the more likely you are to start suffering at the hand of Xenons. People today who have no issue (me) might start suffering later in life.
The tendency of folks to look into the lights and inflict glare on themselves should pass as xenons become more popular (apparently it's the blue edge of the light causes you to light right into the headlamps, where you wouldn't with halogen).
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>> Interesting stuff. The older you get, the more likely you are to start suffering at
>> the hand of Xenons. People today who have no issue (me) might start suffering later
>> in life.
Interesting too that older drivers somehow managed to pilot their vehicles safely for millions of miles and continue to do so without needing lights from the starship enterpise to see where they are going.
The problem with this ever increasing light power of vehicles is that unlit backgrounds....people, animals and background become increasingly more difficult to see, or does only apply to old duffers too..;)
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>> Interesting too that older drivers somehow managed to pilot their vehicles safely for millions of miles
No they didn't --> www.statistics.gov.uk/cci/nugget.asp?id=1208
Interesting dip after the common adoption of xenon headlights there! (i jest, but it is at the right time ~2002 :-P ).
>> is that unlit backgrounds
Behold! BMW Night vision demo --> www.youtube.com/watch?v=-3uaTyNWcBI I want that. If it was possible to retrofit this i'd do it tomorrow but there's no kits yet.
Then there will be other problems identified that need fixing, but it's all forward progress (less accidents, less fatalities).
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>> No they didn't --> www.statistics.gov.uk/cci/nugget.asp?id=1208
>>
>> Interesting dip after the common adoption of xenon headlights there! (i jest, but it is
>> at the right time ~2002 :-P ).
yes they did, cos the ones that didn't are dead according to the statistics, and the ones that managed are indeed us older drivers, i rest my case..;)
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If I had my Xenon HID on in that scenario I'd have seen them easily.
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>>Interesting too that older drivers somehow managed to pilot their vehicles safely for
>>millions of miles and continue to do so without needing lights from the starship enterpise to
>>see where they are going.
Funny that, especially given older eyes need more light as well!
www.agingeye.net/visionbasics/theagingeye.php
"The light adapted eye of a 20 year old receives six times more light than that of an 80 year old. In dark adapted conditions, the 20 year old eye receives about 16 times more light. In comparison to younger people, it is as though older persons were wearing medium-density sunglasses in bright light and extremely dark glasses in dim light."
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>> I suspect that the movement was an illusion caused by the pitching of the car
>> causing your viewpoint to be alternately on and off axis.
Don't understand :( If I'm on axis, presumably they're very bright, and if I'm off axis, they're less so. How does that explain the apparent movement?
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>>Don't understand :( If I'm on axis, presumably they're very bright, and if I'm off axis, they're less so. How does that explain the apparent movement?
It's an illusion ;-)
It has to be - they clearly don't move. But as mentioned, apparently the headlights might. I know nowt about AFS2, but maybe they are moving relative to the DRLs and creating the illusion, in conjunction with the pulsing of the DRL intensity. Both should be illegal.
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>> But as mentioned, apparently the headlights might. I know nowt about AFS2,
>> but maybe they are moving relative to the DRLs
>> and creating the illusion, in conjunction with the pulsing of the DRL intensity.
Don't think so - the headlights appeared to be stationary, while the DRLs moved. Don't remember noticing any change of brightness in either. I'm really intrigued.
EDIT: stationary relative to the car that is (and spelling corrected :)
Last edited by: Focus on Sat 11 Sep 10 at 21:13
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>> Don't think so - the headlights appeared to be stationary, while the DRLs moved. Don't
>> remember noticing any change of brightness in either. I'm really intrigued.
Well they clearly don't move do they? So it was an illusion ;-)
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>> Well they clearly don't move do they? So it was an illusion ;-)
Yes I know! But what's causing it? I mean it's easy to explain why a wheel with spokes rotating at 50Hz can look like it's not moving under a neon light on a 50Hz AC supply, but I'm at a loss to explain this one.
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AFS 2nd Generation doing it's thing?
It really works well and i really notice the difference between AFS2 xenons in the Octy and pre-AFS Xenons in the BMW.
If it was AFS2 doing it's thing, it's the dipped beams were moving relative to the side lights not the otherway round.
They adapt to things like road speed (lift the beam to provide further penetration at night). There's also none of the leveling arms attached to the suspension as there was for AFS1, it's done via optics in the headlight assembly, which if you look at it from below / side, you can see evidence of the setup.
BMW, Skoda & Toyota have been shipping AFS2 for a while. Not sure about VW though which is strange! They're not listed as users of Hella's AFS2 system. Vauxhall get a mention so it's possible.
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For the Devil's Advocate position though, I can clearly remember as a child listening to adults speaking about how these new-fangled radial tyres were dangerous because they would allow some drivers to corner quicker than the rest thus leading to accidents because speed differentials between vehicles would increase. Later in life I recall suckings of teeth at the fitment of ABS to Ford Granadas. There was a widely held urban myth that there would be a concurrent sudden and huge increase in rear end shunts because the Granadas could stop shorter.
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>> Later in life I recall suckings of teeth at the fitment of
>> ABS to Ford Granadas. There was a widely held urban myth that there would be
>> a concurrent sudden and huge increase in rear end shunts because the Granadas could stop
>> shorter.
>>
Funny thing, the1st scorpio granny I saw (local dealers demo) had rear end damage within a week of going on the fleet.
That BTW is 100% true.
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I remember those concerns as well Humph, and disc brakes causing rear end shunts. Remember the triangular "disc brake" stickers on the back of cars? Good job we are an adaptable bunch with a large dose of self survival thrown in (in later years anyway).
Last edited by: Old Navy on Sat 11 Sep 10 at 19:38
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And "air brake" stickers on the back of HGVs...
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In 1834 a (pseudo) scientist by the name of Dr Dionysius Lardner informed Isambard Kingdom Brunel that if the famous Box Tunnel on the Great Western main line was built on a gradient of 1 in 100 a brake failure on a descending train entering the tunnel would mean it would emerge at the other end at 120mph - a speed at which no human could breathe.
Plus ca change...
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>> Brunel that if the famous Box Tunnel on the Great Western main line was built
>> on a gradient of 1 in 100 a brake failure on a descending train entering
>> the tunnel would mean it would emerge at the other end at 120mph - a
>> speed at which no human could breathe.
If i was on a runaway 1834 IKB train through the box tunnel, I for one would be holding my breath.
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>> 1834 IKB train through the box tunnel, I for one would be holding my breath.
Was it really that early Zero? Fabulous cat that Brunel. Smoke would indeed have been a bit of a trial in the open-topped third class at first though. All part of the leading-edge adventure, like being frisked for deadly weapons on the gangway into Concorde, or indeed your elderly Airbus to Alicante.
Great pity Brunel didn't prevail with his 7'6" gauge if you ask me. Then we would have had the TGV before France, and there wouldn't be room for ghastly motorways.
I lived briefly in Box in the mid-fifties, over the cutting at the Bath end of the tunnel. I was 14 and can still smell the house when I think of it.
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"Great pity Brunel didn't prevail with his 7'6" gauge if you ask me."
And me. Whenever I get on a train I think about the relative width of the carriage (about 9') and the track (4' 8") and am always relieved to reach my destination upright...
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I am getting on a bit at 55. rear fog lights dont bother me, brake lights dont bother me, front fogs dont bother me. HID front lights do - its the way they apear to flash up and down that makes them a pain.
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>> the way they apear to flash up and down that makes them a pain.
To be absolutely clear Z this is one of the few occasions when I'm not even slightly trying to be flippant....seriously !
But...I find none of these things bother me if I don't look directly at them. Just avert your eyes slightly and it's not a problem.
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agreed, the flashing makes them distracting tho. to me anyway.
I have strange preripheral vision, for example I can see led rear lights strobe,
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It isn't sidelights though is it? It's dipped beam headlights. Some sorts of lights - Alfas had them - seemed to go overcentre in your mirror in a very sensitive way creating the impression of flashing. But it wasn't monochrome flashing, went all through the main coarse colours of the spectrum, red, green, blue, yellow, seemingly at random.
I still notice it sometimes but not as much as I used to. Perhaps everyone has stuck grey tadpoles on their lamps in the indicated place, as I have just had to do.
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The "bouncing" effect is caused by, I think, a combination of very slight vibration in the mirror and a rapid pulsing of the LED DRLs on the Insignia leading to the impression of the DRL bobbing around.
If one's gaze is flicked from side to side across the back of an LED-equipped car such as, say, an 05-on Passat or most late high-series Mercedes or Lexus, a quick succession of red LEDs can be seen in the peripheral vision as the eyes' focus shifts from one point to the other. I've tried to find a video link to demonstrate this but of course online video is too slow to capture the pulse rate of auto LEDs.
It's for this reason that some of the recent Top Gear footage of expensive Mercedes (I think) seemed to show their LED DRLs and brake lights seemingly pulsing slowly on and off when viewed on TV - a "shutter" effect caused by the combination of the pulsing LEDs and the relatively slow frame rate of the film recording.
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I saw an Insignia tonight albeit driving towards us with LED side lights and headlamps no evidence of bouncing, I would suggest a mirror illusion as well. An acquaintance has bought an A4 and paid for what he describes as "pin lights" he is a wally though.
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>> The "bouncing" effect is caused by, I think, a combination of very slight vibration in
>> the mirror and a rapid pulsing of the LED DRLs on the Insignia leading to
>> the impression of the DRL bobbing around.
Well that sounds plausible Dave, although given the magnitude of the apparent movement, I would have expected everything else in the mirror to be blurred, which it wasn't. So I'm not totally convinced...
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Maybe the self leveling headlights are moving about a bit and the drls are fixed?
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>> Maybe the self leveling headlights are moving about a bit and the drls are fixed?
It wasn't completely dark and I could see the car fairly well - the headlights weren't moving relative to the car, unlike the drls.
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Mirrors do vibrate. I have often noticed that when looking at tractor wheels in the mirror they exhibit that wagon wheel effect in old cowboy films, when the wheels on the stage coach appear to be turning backwards.
I put it down to the the large chunky tyre cleats rotating at about the same frequency as the vibration in the mirror mounting.
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>> Mirrors do vibrate.
Yeah mine do, what is the frequency of Dire Straights money for nothing at 50 watts per channel?
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>> Mirrors do vibrate.
The mirror vibrating at a frequency close to that of the DRLs (they're not DC are they?) would seem like an obvious explanation. However, if the DRLs appear to move up and down through what looks like 5mm on the mirror surface, then I would expect the car's image to be blurred by a similar amount. But it wasn't.
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I just experienced this "bouncing DRLs" for the first time today on an insignia coming towards me. It's the PWM drive of the lights that causes that effect.
I should have clicked before that's what it was, you can recreate the same thing by dragging a (dimmed by PWM) LED through your peripheral vision (rather than directly infront of you / don't focus on it). You'll see it moving about out the corner of your eye, despite the fact it's going in a straight line.
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>> PWM ?
Haha wikipedia helpfully suggests "Pokeweed Mitogen" ?!?!
Pulse width modulation --> en.wikipedia.org/wiki/Pulse-width_modulation
It's basically the idea that you flick the power on and off quickly, so the total light output is less than maximum / dimmed down. It's really common everywhere, your PC might even have an LED on it's case driven this way.
Can be (/is more commonly) used in other contexts than driving LED lights.
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I witnessed the "Bouncing LED" effect this morning. A Mercedes was slowly catching up with me on an almost deserted motorway early this morning. Although the headlights were perfectly steady in a vertical plane the LED DRL's appeared to bounce up and down in my mirror.
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>> I witnessed the "Bouncing LED" effect this morning.
Hurrah! Thanks ON, and apologies to Skoda for missing his similar post.
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Insignia - bouncing sidelights - Manatee
