Cycling UK Forum

Hmmm, cuttting hairs.

LED/HID lights are technically "full spectrum" so appear whiter, but this is beacuse they emit more blue light than filament lamps.

Filament lamps normally have an incomplete spectrum- missing the blue-violet end mainly. Which is why they appear yellower "warmer".

So, there LED/HID lights are bluer, exactly how much tends to depend specifically on the light. When purchasing white LEDs, you can get "warm white" and "cool white" variants- the amount of blue light in the "white" spectrum varies.

Light composition does have effects. The bluer wavelenghts tend to provoke wakefulness, and also, a full-spectrum light makes detailed work easier and colour-matching more acccurate (I use a full-spectrum light for doing fine needlepoint).

LEDS make a huge difference to what sort of light is available- these days, special LED grow-lights are cheaply available as they mix narrow-band wavelength LEDs on a strip to get the optimum wavelenghts for plants (slightly different if growing for foaliage or blooms).

TPo

Helpful explanation thanks.

It was not the intention to split hairs - true "blue" lights are available aftermarket, and are explicitly illegal. You'll note Cunobelin's post earlier thread.

I don't find them bluer, I find them whiter, as I said. You have explained why that's the case.

White LEDs have an excess of blue light beyond what a true white light source would produce. Look at the spectrum for a common whtie LED and note the peak at the blue end, even for the warmer temperatures:

There are high-CRI LEDs that are less blue, but judging ffrom the blinding blue flashes I see every time an oncoming car goes over a speed hump, those aren't common in cars.

gaz wrote:

Asked if there should be better regulation in place to prevent manufacturers fitting vehicles with headlights that are too bright 80% of motorists questioned by the RAC felt this was necessary. Twelve per cent were undecided, and only 8% disagreed.

There are regulations and standards on vehicle lighting to ensure that they are not "too bright". Manufacturers fit lights that meet the regulations.

Is this a suggestion that as well as cheating exhaust emission tests manufacturers are cheating light emission tests too? Do headlights give off more glare in real world use than when they are on test?

The problem is the current standards are based upon power in not light ouput, lights are specified in watts , which worked well for filament lights, current technology means lights are brighter. The standards need changing to take into account light output.

According to CJ's post here, the standards did take into account light output (e.g. candela):

Motor vehicles must be ‘type approved’ before they can be used on the road and as part of that approval their lighting must conform with ECE regulations. These regulations ensure that headlamps do not dazzle other road users by putting a top limit on the intensity of light emitted above the horizontal (and to the offside) by a dipped headlamp. For technical reasons different types of lamp have different limits, but the most an oncoming road user should see from any ECE approved headlamp, when dipped, is 625 candela.

The comment "different types of lamp have different limits" referred to halogen lights having a lower limit (437cd).

Mr Evil wrote:...There are high-CRI LEDs that are less blue, but judging ffrom the blinding blue flashes I see every time an oncoming car goes over a speed hump, those aren't common in cars.

I think this is due to BMW/Mercedes premature introduction of HIDs (before they had good CRI), has led to marketing persons inventing gibberish about blue lights and now we are plagued with the idea that blue white headlamps are (slang) 'cool' as well as (insert marketing gibberish pretending they are better).

Its also annoying that LED cyclelamps offer little opportunity to choose less blue shades of LED (My requests to B&M to offer just one (eg Cyo premium hub senso standlicht) with a warm/neutral LED option fall on deaf ears.... Grrrr)

Can one put a filter or a bit of tape over the lens?

I agree with the RAC , I am frequently hit by what I consider to be high beams which aren't

And if we are on dishonourable mentions the Local Mountain Bike crowd need a gentle reminder that 4 million lumens (or whatever it is)? on a helmet lamp is probably fine in the woods but it does not endear them to passing motorists in a well lit urban road.

Cyril Haearn wrote:Can one put a filter or a bit of tape over the lens?

No. But The dipped-ness of ECE lamps is adjustable .
But the Sharp cutoff of UN ECE lamps should make them easier to aim: I think, on level ground, parking 25m from a wall then ensuring, that at the wall, top of cut-off has dropped the % marked on car (eg 1.3%) where that % is the height of the optical centre of the headlamp...because that is kind of mentioned in a regulation but is it a test setup, and does that matter: an RAC version of CJ is required.....


I think the RAC need an a technical person who understands the UN-ECE standards and can decode them for ordinary mortals.. They could then have a lighting page....which instructed people how to ensure their dipped headlamps were actually dipped.

I think the big problem is people with the dipped setting up too high. I suspect most people don't even know where the control for this is on their cars and given most cars seem to be left to the '0' setting as a default which is the highest setting intended for a loading of both front seats and nothing in the back or boot combined with the modern stupidly bright bluey xenons (I don't think these are actually LEDs?) and it's not surprising that this is an issue.

I don't think the plague of chelsea tractors helps either as the headlamps are mounted almost as high as the head position of someone in a sensible car so even when 'dipped' the slightest bump will dazzle oncoming vehicles.

Stevek76 wrote:I think the big problem is people with the dipped setting up too high. I suspect most people don't even know where the control for this is on their cars and given most cars seem to be left to the '0' setting as a default which is the highest setting intended for a loading of both front seats and nothing in the back or boot combined with the modern stupidly bright bluey xenons (I don't think these are actually LEDs?) and it's not surprising that this is an issue.

I don't think the plague of chelsea tractors helps either as the headlamps are mounted almost as high as the head position of someone in a sensible car so even when 'dipped' the slightest bump will dazzle oncoming vehicles.

Xenons auto-level IIRC. It's only the older bulbs that have a manual adjuster.

Stevek76 wrote:II don't think the plague of chelsea tractors helps either as the headlamps are mounted almost as high...

The UN-ECE rules actually require higher mounted headlamps to be dipped down by more to compensate for higher mounting (currently only two dip levels for low mount vs high mount but they are proposing more sliding scale). But that only works if people keep their headlamps adjusted. But Chelsea tractor lamps are higher I had noticed any at ordinary plebian car driver eye level. I think the max height is 1.2m

Stevek76 wrote:I think the big problem is people with the dipped setting up too high.

+1
But I also wonder if garage headlamp aim test equipment for MOT is being used correctly etc? Perhaps the low tech of a wall is more reliable?
I wonder if auto level gets confused/jammed.
Surely ECE dipped headlamps' sharp cut-off should make them easy to set by hand when a set distance from a vertical wall on level ground (as I alluded to above): perhaps this should be in Highway code or at least publicised in easily understandable form by Gov/AA/RAC?

I also think headlamp design may have been compromised by fashion: I suspect fresnel len lamps might be less dazzling than modern clear lens ones (because the fine fresnel acts like a diffuser meaning for dipped beam the lens is more evenly illuminated?).

When I look at ECE reg on H4 Halogen bulbs the allowed variation on dipped lumens is +-15% so how can ones marked as 90% brighter meet that? eg http://catalog.hella.com/catalog/produc ... 20525-531/

A related problem that came close to making the Pet Hates thread is drivers parking/hovering by the right hand side of the road with their dipped beams on. Too often they forget that the beam is dipped a lot less on the left, thus illuminating a lot of hedge while driving and a lot of oncoming eyes while parked on the 'wrong' side.

Pastychomper wrote:A related problem that came close to making the Pet Hates thread is drivers parking/hovering by the right hand side of the road with their dipped beams on. Too often they forget that the beam is dipped a lot less on the left, thus illuminating a lot of hedge while driving and a lot of oncoming eyes while parked on the 'wrong' side.

Or several thousand lumen lights wielding cyclists on n the left of the road (from oncoming vehicle's pov) facing oncoming traffic. I had the pleasure of losing all sight of where the road was due to two such roadie cyclists once. One of them also had a very bright head torch that I thought would blind me but by that time the bike mounted lights had done that job just fine.

BTW what's the procedure on such cases? Should I drive through or brake hard, get out and turn them off with a polite smile and manner? BTW I chose to drive past but fortunately the was no oncoming car to hit despite me ending up halfway into the other lane. It's funny how you kind of panic when your retinas get burned out and you suddenly develop a bad wobble in your steering.

Tangled Metal wrote:

Pastychomper wrote:A related problem that came close to making the Pet Hates thread is drivers parking/hovering by the right hand side of the road with their dipped beams on. Too often they forget that the beam is dipped a lot less on the left, thus illuminating a lot of hedge while driving and a lot of oncoming eyes while parked on the 'wrong' side.

Or several thousand lumen lights wielding cyclists on n the left of the road (from oncoming vehicle's pov) facing oncoming traffic. I had the pleasure of losing all sight of where the road was due to two such roadie cyclists once. One of them also had a very bright head torch that I thought would blind me but by that time the bike mounted lights had done that job just fine.

BTW what's the procedure on such cases? Should I drive through or brake hard, get out and turn them off with a polite smile and manner? BTW I chose to drive past but fortunately the was no oncoming car to hit despite me ending up halfway into the other lane. It's funny how you kind of panic when your retinas get burned out and you suddenly develop a bad wobble in your steering.

Are you seriously asking what the correct response is when you are driving a car and can no longer see the road in front of you due to dazzle?
I have been in that situation a few times and know that I should not proceed if I cannot see the road ahead to be clear. On at least one occasion (dazzled by the headlights of an oncoming bus), this has saved me from driving into a pedestrian in the road.
Please if in the future you are dazzled, stop or at least slow to a speed at which you can see the road ahead is clear. This equally applies to dazzle by low sun or overly-reflective road signs.