lds

Motorcycle Visibility for Dummies

Jul 08, 2011 19:33


I don't have time to completely revise a post I made for another audience some time ago on motorcycle visibility, but since I went public with my "Loud Pipes Save Lives" post, I need to at least hit the high points on motorcycle visibility, as well. As before, let's start with the facts.

As with any other physical objects on our planet, there are two ways motorcycles can be perceived with our sense of sight: either by the light they emit themselves, or the light they reflect from other sources. I'll discuss these two groupings individually.

Generated Light

There are three factors that influence our ability to see and process lights as something relevant to our driving: intensity, surface area, and color (hue). A change in any of these three factors is more noticeable than a light that stays constant. Here are a few examples:
  • A "taillight" is a red light that stays on all the time, that provides the most basic level of visual cue. It doesn't change color, intensity, or surface area until there's something else going on that other drivers should be aware of.
  • A "brake light" can be a tail light that changes intensity, from dim to bright, to indicate that there's something that needs a trailing driver's attention. On cars, years ago, brake lights used to be this and nothing more, but I think in the 1990s, "eye-level brake lights" became required by law on new vehicles too: these change not only the intensity of the taillights, but change the total surface area, as well. Intensity and surface area both changing are better attention-getters than just intensity alone.
  • A "turn signal" on a car may be a different color than a marker light. Pay attention to cars at night: some have amber turn signals, but some have red. Regardless of color change, though, they usually change surface area, and they always flash, which means they are constantly changing in intensity.
  • As we looked at extreme cases of life-or-death in the "loud pipes" post, let's consider how they do lights on emergency vehicles when your attention is required immediately and constantly: multiple hues are used; we can find examples of orange (amber), vivid yellow (usually on LED strobes), red, blue, and white. We find rapidly- and constantly-changing surface area, and lots and lots and lots of intensity changes, also rapidly- and constantly-changing. "Pour it all on, hoss," they ask of their emergency flasher vendors. "We'll take lots of all of the above."
How do we implement these three techniques of attention-capturing on motorcycles? Here are more examples:
  • Most standard motorcycles have only a single taillight and two turn signals in the rear. The taillight changes in intensity only when the brake is applied. Turn signals are amber, so when they're used, they add a new color, new surface area, and a new intensity level.
  • On the "Dark Custom" series of Sportsters, Harley-Davidson has eliminated the taillight entirely and put red lenses on the turn signals. Both braking and turning is signaled by altering the intensity only; color and surface area remain unchanged. Harley responded to a demand for "more light" by us hard-to-please customers by offering an LED strip that mounts under the bobbed rear fender and replaces the missing taillight/brakelight combo functionality. The combo turn/brake/run lights retain their multi-function capability, so at all times, these "Dark Customs" with the LED taillight now have more lit surface area than most standard motorcycles.
  • A common modification (which I have done to my bikes) to get this same increased amount of illuminated surface area on most other bikes is to replace amber turn signal lenses with red ones and install a turn/brake/run module. Now braking is signalled by a change of intensity across three times the surface area of a stock bike.
  • Another common modification is to replace incandescent bulbs on the rear of the bike with LEDs, and the users and reviewers emphasize low power draw that means greater brightness is possible. The increased longevity of LEDs over incandescents is nice, but what we really crave is intensity, intensity, intensity! And those LEDs do get bright, fortunately for us!
  • Big touring bikes have more rear surface area on which to plaster more lights, so big touring riders make use of it. The accessory catalogs, factory and aftermarket alike, are full of add-on lights. Even from the factory, the Ultra Classic Electra Glide has additional lights on the bottom of the trunk and along the sides. There are even high-current-draw alternators for the light junkies to get enough.
  • On the front of a typical motorcycle, we find one headlight and two amber marker/turn signal lights. Again, it's popular to replace the incandescent markers with LEDs for added intensity.
  • And, just over the past year, LED headlights have made enough technological improvement that they are becoming serious contenders for the intensity wars. Harley-Davidson is one of the first manufacturers to offer LED headlights, and there are a few aftermarket vendors spinning up quick. The selling pitch? Intensity, intensity, intensity! They're still very expensive, but becoming popular surprisingly quickly.
  • But what about surface area on the front? Harley and Harley knockoffs offer light bars with passing lamps, and there are fog lamp kits for most touring and adventure-touring bikes. These are popular accessories, and not only do I ride with my passing lamps on day and night, but I've also installed them on zophine's bike as aftermarket accessories.
  • There is plenty of debate on Gold Wing and other touring forums about the value of headlight modulators, that create a gentle intensity fluctuation. Some people say they "are annoying" and "cause other drivers to get target fixation" and head-on the bike, but I haven't seen any data to support this yet. If we follow the "extreme" example above from emergency vehicles, headlight modulators certainly do fit the "pour it all on hoss" philosophy. I don't have any, but certainly wouldn't criticize anyone who uses them for being "annoying."

Now let's talk about a different approach to lighting:

On racetracks, glass is often not permitted because of the danger it can cause to other racers in the event of a crash. (Remember Lightning McQueen's nickname in the Disney movie Cars? They called him "Stickers" because he didn't have real headlights, but just stickers that looked like headlights.) Racers don't use turn signals, either. There is a subset of motorcyclists who make it their highest priority to look like a pro racer. This is an aspiration to the "coolness" of success in motorsports without actually winning any races. Here are the implications of this value system on motorcycle lighting, and visibility to other drivers:
  • These riders make their turn signals as small as possible. The dealers' accessory racks feature super-tiny arrow-shaped LED turn signals that dramatically reduce the surface area from the factory stock signals.
  • Run/brake/turn modules sold to the cruising/touring market work the same on race bikes, but if anyone's seen such a module used to increase brake/marker surface area on one, let me know. I don't think I've ever seen it.
  • Sometimes brake lights double as turn signals, with the red outer tip of the brake light changing to amber to signal a turn. This means that there is no change of intensity and no change of surface area, but only a change in color. A change in color is better than no signal at all, I suppose.
  • On the front of race bikes, there are usually two headlights, but one is for low beam and one is for high beam, so even though there are two, one can only change intensity and not surface area. Aftermarket fog lamp and auxiliary lamp kits are rarely seen on race bikes used on the street.

So, as I pointed out in my "loud pipes" post about how race bikes can't quite use loud pipes to increase driver awareness the way V-twins can, so we also find that race bikes sometimes don't use lights to increase driver awareness either.

Reflected Light

Reflected light can also be used to increase driver awareness, but there are many differing philosophies on how best to put it to use. The main point here is that reflected light is very, very rarely more intense than generated light, and is far more "natural" than generated light so it is more easily overlooked. Nonetheless, ambulances make use of interesting color patterns in my town to catch drivers' attention, and our firetrucks are nicely chromed out, so let's look at a few ways reflected light is used by motorcyclists as well.
  • First we should consider that motorcycles are required by law to come from the factory with reflectors installed. I've seen a few folks on all kinds of forums-Harley-centric, touring, and race bikes alike-who like to pull the reflectors off, but I don't know anybody personally who's done this. I don't think it's very common.
  • Gold Wings are the only bikes I've ever seen that use brightly chromed helmet locks dangling from the trunk to catch the sun (or headlights) in a moving, flashing passive light show, like gardeners use tin pie plates hung from sticks to scare off birds from their produce. Neat idea, but I think the configuration of the trunk on a Gold Wing lends itself to this use rather exclusively. If I had one, I would probably do this.
  • "Blacked out" bikes have become trendy in recent years, as my prior mention of Harley's "Dark Custom" line demonstrates. They even come with names like "Blackline" and "Nightster" to emphasize this design "feature." They use blacked-out handlebars, turn signal nacelles, engine bars, sometimes even exhausts: many components that have traditionally been chrome. My Sportster is one of these "Dark Customs," and I'm slowly replacing the blacked-out components with more chrome for greater reflectivity. Lots of curved surfaces have traditionally been chromed for aesthetic reasons, but there's probably a Darwinian selection force at play too: more chrome means more reflection and more numerous specular highlights to catch other drivers' attentions. The mirror finish of chrome means these reflections can be effective both by sunlight and in headlight and streetlamp glow at night, but each curved surface represents only one point of light. To determine chrome's value to visibility, then, we calculate not the number of square inches of stuff, but we count how many curved surfaces are reflecting a single point of light each.
  • Brightly-colored clothing is often the only use of reflective light that's mentioned in safety briefings, but clothing, even the construction-worker yellow and orange type, is rarely as reflective as the plastic reflectors from the factory and chrome. They're pretty much never as intense as generated light from taillights and such either. I think they're mostly mentioned because they're easy and inexpensive, so if one absolutely must have a blacked-out bike with few and small lights, such clothing is a pretty good idea... the "least one can do," so to speak. One benefit of bright clothing is that, for some of us, our torsos present a pretty good surface to increase visible surface area. This is less valuable on touring bikes with trunks and fairings, but as noted above, that's a good tradeoff because trunks and fairings are great places to add lots of lights!

Now, as I pointed out in my "loud pipes" post, all visibility enhancements are limited by a major shortcoming of human biology: our sense of sight is far more directional than our sense of hearing. Nonetheless, an "all-of-the-above" approach is superior to relying on any one sense or strategy for our safety, so unlike my un-implemented preference toward loud pipes, I do actually find myself soldering wires to add lights wherever I see an opportunity to do so.
Previous post Next post
Up