Photo 1: (L to R) OEM white H4; Hella; Nokya

Motorcycle Light Bulbs - Improving Visibility With Yellow Bulbs?

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by Bill C. for webBikeWorld

There are many wonderful and unique things to do and to see in France.  One of the most curious for me was the use of the very  distinctive yellow headlights on cars in France about 20 years ago or so. 

They looked so...different.  Every once and a while, a car with yellow headlights will pass by on a European road; however, it's my understanding that yellow lights are no longer legal in France or anywhere in Europe, except for auxiliary fog lights.  But European drivers and motorcyclists will always bend the rules, just like we do here in the U.S.A., and using yellow headlights is one way to look different.

I never really knew why the cars in France had yellow headlights, but I'm told that yellow bulbs can provide better visibility in poor weather because they provide greater contrast.

Although yellow headlights are virtually non-existent in the U.S.A., daytime running lights (DRL's), which were originally intended to make a car more visible, have become very common over the last decade or so.  DRL's are also mandatory in Canada, Denmark, Finland, Hungary, Iceland, Norway, and Sweden (from the Insurance Institute for Highway Safety).  Some states in the U.S.A. also require the headlights to be on during poor weather conditions or whenever the windshield wipers are used during a rain storm.

There is some debate as to the effectiveness of DRLs in making vehicles more visible to other traffic.  DRLs are supposed to increase conspicuity, but if every vehicle has headlights burning, any one vehicle with headlights on may no longer be as conspicuous.  It's like saying that by painting a car the "safety orange" color, it will be more visible to others.  But if all cars were painted safety orange, then what?

For our purposes as motorcyclists, that argument is irrelevant.  What interests us is the conspicuity or visibility of our motorcycles to other vehicles sharing the road.  Since daytime running lights are now legal in the U.S.A. and other parts of the world, one of the few methods we had to make ourselves more distinctive -- using our headlights whilst riding -- is nowhere near as effective, because so many other vehicles are doing the same.

We have many articles related to motorcycle lighting, visibility and conspicuity posted on webBikeWorld.  Please take a look at the webBikeWorld review article index and the maintenance, repair and technical article index for reviews and articles on motorcycle brake lights, LED lighting, headlight modulators and more, all of which can help improve conspicuity and visibility.  This article is just one of a series of continuing studies on improving motorcycle visibility.  We make no claims as to the scientific accuracy of any of the articles.  This is purely subjective information and our opinions on various products that might help.

Can Yellow Headlights Make a Difference?
In a sea of daytime running lights, SUV's, cell phones, in-dash GPS and DVD systems and all of the other madness and chaos on the roads today, a motorcyclist must use every trick and technique possible to stand out from the crowd.  Bright orange or yellow helmets work very well, and are at a location high enough to make a difference.  Unfortunately, those colors (especially bright orange) are not very popular for helmets.  Bright motorcycle clothing and lighting may also make a difference.

I've always had those yellow French headlights in the back of my mind, and recently decided to see if I could locate a set and try some experiments in motorcycle lighting to see if they would make a motorcycle stand out from the crowd.  Although yellow may not be the best color for ultimate headlight visibility, I postulate that the color is different enough from normal "white" headlights that it will help make a motorcycle more conspicuous.

This is especially important for oncoming traffic.  The famous Hurt Study, the results of which are still valid, indicated that one of the most frequent causes of motorcycle accidents is when an oncoming vehicle turns left in front of a motorcycle because the driver didn't notice it. 

There have been some unscientific studies that I've read over the years that correlate vehicle size with conspicuity.  In other words, a small motorcycle, even with headlights blazing, has a small cross section which causes oncoming vehicles to grossly misjudge the speed and distance of the oncoming bike, and the bike appears much farther away than it really is.

One other aspect of the issue of motorcycle headlights and conspicuity to consider is the brightness of the headlights.  Some motorcyclists use high beams during the day, and I've noticed many cruisers with a three-headlight light bar where the outside lights are deliberately pointed at oncoming traffic.  I'm of the opinion that this is very annoying to oncoming drivers and the brightness of the lights may actually cause the motorcycle to actually be less visible.  This is because the bulk of the motorcycle can sometimes "disappear" behind the dazzling brightness of the headlights.

Also, the dazzling bright lights may prevent the oncoming driver from noticing the motorcycle's directional lights.  Motorcycle directionals are usually wimpy little 20 Watt bulbs behind a couple of square inches of yellow plastic, and they can be easily be lost in the dazzle caused by the motorcycle's high beam.  The dazzling bright headlights can most definitely distort the ability to determine the motorcycle's speed and distance to the oncoming vehicle.

That's why I almost never use the high beams when riding a motorcycle during the daytime.  I also do not modulate the high beam when using a headlight modulator, and I will only use modulators that have the ability to modulate the low beam.  It is my contention that it isn't so much the ultimate power of the light but the quality that makes a difference.

Which brings us back to the yellow headlight bulbs.  The emphasis lately seems to be towards bulbs providing "whiter" light, such as Xenon gas filled or HID lighting.  Light "color" is measured in Kelvin "temperature", although the K value can be very misleading and is not very meaningful for actual light output.  The so-called "whiter" bulbs have something like a 3000°K to 4000°K color temperature, whilst some of the HID bulbs can get up to 5400°K, which is nearly equivalent to the color of sunlight on a sunny day around noon (5500°K).

Since I never go with the crowd, my desire was to go in the opposite direction, down to around 2000°K to 2500°K, about the same color as candlelight. 

The popularity of customizing cars and motorcycles has opened up lots of options for anyone wishing to experiment with lighting, making it fairly easy to find bulbs of all different color temperatures and types.  Colored bulbs are also available; that is, bulbs with special coatings on the glass that provide various intensities color saturation that enhance or change the actual color temperature of the bulb itself.

One of the claimed benefits of yellow headlights is better perception in fog or misty weather.  I found yellow bulbs in the standard 60/55W output that is most common (and legal) in the U.S.A.   However, since the yellow light seems to be "dimmer" than the white light, I decided to jump one level in power and go for the 80/70W versions.

Since anything over about 80W or so greatly increases the probability of problems with the motorcycle's electrical system and with the possible melting of the plastic lens and reflector, bulbs above 80W should be avoided.

Also, the yellow bulbs are not legal in the U.S., and cranking them up to 110W or so probably would make the motorcycle just that much more of a target for ambitious law enforcement.

I didn't want to spend a fortune on this experiment, and I found two different bulb types to try.  One is the Hella "Yellowstar" bulb, claimed to have a 2500°K color temperature.  These are available in the standard 60/55W and also in 80/70W, 110/85W and 130/90W.  I purchased the 80/70W bulbs from Rally Lights, a Hella retailer, for $10.18 each.  When lit, the bulbs seem to have the same level of perceived brightness as the original equipment "white" 60/55W H4's in the Triumph Tiger that we used for our trials.

I also purchased a pair of Nokya Hyper Yellow Pro Halogen bulbs from Automotive Lighting USA for $22.99 the pair.  These have a 2500°K bulb plus a strong yellow coating on the glass.  The bulbs are advertised as 80/70W and the box they came in claims the same, but the metal base on each bulb is stamped "60/55W". 

We contacted Automotive Lighting USA about this discrepancy; they wrote back: "Many of the bulbs Nokya uses have the same bases to cut down on manufacturing costs.  The bulbs you received are 70/80w bulbs as shown on the package.  The 55/60w engraved on the base of the bulbs is just a standard Nokya base used for other lights.  The bulbs you receive are the Wattage shown on the package." 

Hmmmm...I wonder.   The point is that there is much confusion and obfuscation in the world of headlight bulbs with regards to output claims, like the "55W bulbs with a 100W output", so be careful.  I'm not saying that Nokya is deceitful, but it's sure hard to tell when the base is stamped with a different output number than the box.

For the record, my experience with both Rally Lights and Automotive Lighting USA is very positive, as both companies answered all my questions prior to the sale and shipped the products immediately.  The Hella bulbs were damaged twice in shipment, and Rally Lights immediately sent another pair without question and didn't even require sending back the damaged bulbs for proof.  Automotive Lighting USA has a large selection of bulbs of many different types and from many different manufacturers, and they answered my pre-sale questions and shipment was immediate.

Comparison of H4 Bulbs
Changing the bulbs on the Tiger is relatively easy, because the bulbs can be accessed by reaching up under the fairing without having to remove any parts.  However, we discovered that it's very difficult to take photographs that do justice to the color temperature of the light bulbs.  The differences, while dramatic to the human observer, are not that apparent in the photos.

The "yellowness" of the light is apparent, but hard to differentiate, in the photos.  We tried several different locations, distances, focal lengths, shutter speeds, etc., but these seemed to be the best we could get.  We also tried taking photos in bright daylight at a distance of several hundred feet, but the results also didn't really show the difference well enough to include here.

So, you'll have to take my word for it!  Photo 2 shows the original equipment, 60/55W "white" halogen lights.  They appear slightly yellow in the photo, which is normal, and is apparent if you've ever seen the difference between standard automotive lights and the "blue white" HID lights now available in some cars.

Photo 3 shows the Hella Yellowstar bulbs.  You can see in the reflection on the fairing surrounding the light that there is a slightly more yellow cast.  But the difference shown here is about the same as it is when viewing them "live".  The Yellowstars are slightly more yellow, but they don't have the dramatic difference I was searching for.  When taken out of the package, the Hella bulbs have a slight yellow tint, but the clear glass housing around the filaments looks clear.

Photo 4 shows the Nokya Hyper Yellow bulbs.  These bulbs have some type of yellow coating on the clear glass housing around the filaments.  Apparently, this helps to give the bulbs their very yellow cast.  The difference is not that apparent in the photos above, but a faster shutter speed demonstrates this difference in Photo 5 below:

Conclusion
I am pleased with the outcome of this very unscientific experiment.  The Nokya bulbs have a very yellow and very distinctive color, and many people have commented on them, so they must be doing their job.  Until someone conducts proper testing and analysis, the issue of visibility will be purely conjecture, but my opinion is that these bulbs will definitely make a motorcycle stand out from the crowd.

It remains to be seen how long the Nokya bulbs will last during the stresses experienced with motorcycle use.  We're also planning to install a headlight modulator on this bike with these bulbs, so stay tuned!

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►Owner Comments

From "M.C.":  "... I have done a much simpler survey of the effects of yellow front lights on getting noticed. Several years ago I had a H-D FLH with the stock tractor light bar and a replacement Hella headlight. I had installed a 55/100W bulb prior to any other work. The tractor light bar refers to the type of lights they installed on the light bar.

There was a corner near my home that I could bet you my pink slip (certificate of ownership) a car would pull out in front of me if one was at the entrance/exit from the shopping center onto the highway.  Now my FLH had the fairing and presented no small frontal area. Fortunately, I had one of the 4" lights go out. 

In researching what was available, I found that 4" was a common size for spot lights.  I resisted the urge to get a blue and a red light (all sealed beam) as the gendarmes would get the wrong idea for sure (yes Virginia, I would be noticed).  But I decided to try the yellow, as I figured that I might be seen better in the fog (I lived along the Central California coast at the time -- tough place to live with a motorcycle), if nowhere else.  ALL the difference in the world!

Where before I could guarantee a car would pull out in front of me, now I could make the opposite bet as long as I had the light bar on.  The headlight and/or the clear light bar lights made no difference, but the yellow did.  Today almost all vehicles on the road have halogen lamps for headlights.  When you see a vehicle with a yellow set of headlights, you notice it (even if it's just sub-concious), and that's just the old cars, not the yellow that this article references.  I would suggest showing the effects in doing the light bars on cruisers separate from the headlights as well."