HEADLAMP MODULATORS FOR MOTORCYCLES:
Music Selection:  "I Saw the Light!"
Appropriate, eh?


Modulator Background:

In the early 1970s came a tremendous surge in motorcycle sales.  The reasons are many:  A generation of "baby-boomers" had reached legal driving age; the first OPEC oil embargo and the subsequent gasoline shortage made travel by motorcycle much more economical than driving a car; the Japanese motorcycle manufacturers were challenging the domestic American and British manufacturers for cycle supremacy and gaining rapidly as the British manufacturers -- Triumph, BSA, Norton, et.al. were losing their market (and survival) to the competition.

The 70s surge in motorcycle sales was followed by a whole lot of auto-motorcycle collisions.  Analyses of the events leading to collisions, such as "The Hurt Study" (See Note 1 Below) on the cause of the accident rate increase showed that all these new motorcyclists were essentially "invisible" to other motorists, mostly in automobiles.  In an effort to help the motorcyclist become more visible on the road, many states passed mandatory lights-on laws.  Headlamps were required to be turned on whenever the cycle was in operation.  Lighted headlamps provided a decrease in the number of auto-cycle collisions and fatalities.  In the 1980s, many motorcycles (primarily the Japanese) were manufactured with the headlight switch either electrically defeated or eliminated altogether.  The headlamp would constantly be lighted whenever the engine was running, by design.

This improved the cyclist's visibility to the other vehicles in front of him without any action whatsoever on the part of the cyclist.

Since having one's headlights on improves vehicle head-on recognition to other vehicles (and because the inept public lacks the common sense to turn on headlights during dawn/dusk, fog, rain, snow, smoke and other poor-visibility conditions) some automobile manufacturers, and most notably General Motors, began installing Daytime Running Lights - DRLs - as standard equipment on their autos.  DRLs automatically operate the auto's high-beam lamps at reduced voltage (less brightness) whenever the ignition switch is on, with NO operator action... which is a good idea to make cars more visible in reduced-visibility situations, but is a bad idea for motorcyclists who then lost their safety edge from having their lights on all the time.  Now with the common use of DRLs, a motorcycle could be lost in a "sea" of turned-on headlights during daylight conditions.  Something was needed to make the motorcycle stand out from the crowd once again.  Enter the 1990s and development of the motorcycle headlight modulator.  With a modulator installed, the motorcyclist is once again able to be differentiated from other traffic, with the headlight pulsating, varying between two degrees of brightness.

The flickering of the high-beam is unmistakable.  Disliked by some, misunderstood by many, it is seen by all.  Simply put, MODULATORS GET YOU NOTICED !  And being noticed improves the odds that you'll be seen by an inattentive driver, ergo the chance for a collision with an auto is reduced.

Headlight modulator installation is recommended for the cycle's HIGH beam element, although it is legal on either high or low beam.  The reason the high beam is preferred is because the high beam pattern illuminates the area to the center and left of the bike's centerline, which is the direction from which the majority of auto-cycle collisions occur... especially oncoming cars turning left in front of the cycle.  The low beam pattern tends to illuminate the area to the center and right of the bike's centerline, a location where fewer auto-cycle collisions seem to originate.  A common comment frequently reported in post-accident investigation dialogue is the auto driver saying "I never saw him."  Perhaps it's because the driver wasn't looking at the cyclist, or looked "right through" the cyclist, not taking note of his presence.  With a headlight modulator operating the high beam of the headlight, there is less potential for that statement to be made.

As I said... MODULATORS  GET  YOU  NOTICED !

An important distinction that you should be aware of if you are considering the purchase of a modulator or defending its use, is that the modulating headlamp DOES  NOT  FLASH!  Flashing is defined as the rapid turning on and turning off of power to the lamp.  With a headlight modulator, the lamp never turns off, but rather power is varied between two different power levels at a specific rate of speed.  Therefore it does not flash.  It simply modulates (or pulsates, shimmers, twinkles or flickers, if you prefer)...  Flashing lights are illegal on all but emergency vehicles.  But Modulating lights are legal.   But keep in mind that they are legal on motorcycles only.  Automobiles are not permitted to have modulating headlamps.


Tell Me More...

Four questions typically come up in conversations about headlamp modulators:

1.  Isn't it hard to drive at night with the light flickering like that?

NO.  There is a photo-sensor that disables the modulator circuitry once daylight falls below a pre-set level.  As dusk approaches, the lower intensity of ambient light hitting the photo-sensor will tend to turn the modulator off, especially when driving under the canopy of overhanging trees or in and out of "shadow" areas.  When that begins to happen, you'll know it.  Reflected light from signs and roadside reflectors will make the light's change from modulation to steady high-beam apparent.  It's time to switch to low-beam.

2.  Won't my headlight bulb burn out from all that flickering?

NO again.  Since the average power applied to the bulb filament is lower, the use of a modulator actually extends the usable lifetime of the modulated headlamp's bulb.

3.  How will I know if my modulator is working while I'm riding?

Between the reflections you'll see from road signs and the pulsation of the high-beam indicator light (usually a small blue light or jewel lens) you will be aware that the modulator is working.  The high-beam indicator will flicker right along with the headlight.  It's normal.  It tells you that everything's working just fine.

4.  Will a modulator keep deer and other animals out of my path?

The jury is still out on this one, but likely to return an unpleasant verdict.  Generally, I'd say "no" because I've observed mixed responses from deer while riding ranging from flight -- to staring at me approaching -- to total disregard of my presence.  There is no consistent response, so I'd say that any number of factors may influence the behavior of deer, and lighting is but one source of their possible panic.  But so is sound.  Cranking up the stereo on my GoldWing is as effective at keeping deer away as the modulating headlight, and perhaps more so.  When deer are in rut (late fall-early winter) NOTHING will distract a buck... he's got one thing, and one thing ONLY in mind, and motorcycles aren't it.  Don't expect a headlight modulator to be your salvation in deer-infested areas.  Only a watchful eye, moderate speed, and a couple fingers on the brake lever will help.  And limit your travel time to avoid dusk & dawn (deer's typical movement times) if you can.


Headlight Modulator Etiquette:

During the Motorcycle Safety Foundation's Experienced Rider Course I took during the summer of 2001, there was considerable debate over the proper way to "use" the modulator.  While use of a modulator is indeed legal, some common sense should be used while it is in operation.  Since it can be switched on and off at will using the headlight dimmer switch, there are times and situations in which it is reasonable and proper to turn it off: 

  When you are sitting behind a vehicle in traffic, your modulator can be a nuisance to the driver in front of you.  This is especially true if you are far enough behind the other vehicle for your headlamp to shine in the driver's rear-view mirror.

  When you are sitting at a red traffic light waiting to proceed through the intersection with nothing in front of you to block the light, your modulator may be a nuisance to a driver on the other side of the intersection facing you.  Give him a break.  Dim your headlight (turn off the modulator) until the traffic light turns green and you can proceed.

  If you are going to be stationary behind any vehicle for more than a few minutes, do the driver ahead of you a favor.  After following someone for a while, it will become clearly obvious to you that the driver in front has noticed you.  Put your headlight on low beam (modulator off) until you prepare to pass the driver.

  Turn off your modulator when you are riding in a group, unless you are the lead bike.  The lead bike's modulator will stimulate enough of the oncoming driver's attention for the whole group.    If you're riding in the  "drag" or "sweep" position, you can give the leader an occasional "twinkle" on a long straightaway to let the tour leader know how far back the tail end of the group is, without being an annoyance to the rest of the group.   (This applies more to LARGE group rides like Americade's mini-tours, where there may be 50-60+ bikes in the tour group.)

Our MSF Instructor suggested switching off the modulator in metropolitan or suburban areas where the streets are congested and one must frequently sit in traffic.  Those who use modulators (myself included) argued that city & suburban driving is more risky than country riding due to the higher number of vehicles, and the greater number of people pulling into traffic from intersections and side entryways.  Furthermore, there are many more vehicles blocking you from view, limiting the ability to be seen by others.  Therefore, use of the modulator is that much more important in the city.  Eventually, he conceded... he wasn't about to win that verbal battle!

Keep common courtesy in mind.  Remember that a modulating high beam can be as much of an assault on one's eyes as loud pipes are on one's ears.  Act accordingly.  Act responsibly.  And remember that the impression you leave on the public reflects on ALL motorcyclists!


The Modulator Law:

The law that permits use of headlight modulators for motorcycles may be found in Title 49 of the Code of Federal Regulations, which is typically abbreviated 49CFR.  The CFR is a set of books containing various federal laws and standards, broken down in volumes by "title".  Each title deals with subject matter about a specific topic.

The CFR can usually be found in the reference area of any public library.  It can also be found on-line using your browser and searching for "Code of Federal Regulations", although it takes significant "drilling" to find exactly what you're looking for.  For that reason, I have posted the entire relevant text here, at the bottom of this page.

The specific regulation on modulators is 49CFR Section 571.108, paragraph S7.9.4, entitled "Motorcycle Headlamp Modulation System."  I copied the entire section from the CFR, which amounts to a little less than a full page of the hard-bound copy, and I keep copies with me on my bike as backup data for the excerpts printed on the literature that came from Kisan Technologies, Inc., the manufacturer of my modulator.  I also keep copies of Kisan's literature with me.  I make sure I have sufficient copies with me such that when I am stopped (and it DOES happen occasionally) that I can provide a tear-away copy to give the law-enforcement officer for his benefit and the benefit of those back at the police station.  I turn the traffic stop into an informative experience for the police officer, and give him something he can use to educate his fellow officers.

WHAT IS NOTEWORTHY AND DESERVES MENTION HERE IS THAT NO U.S. STATE OR MUNICIPALITY  MAY USURP (OVERRULE) THE AUTHORITY OF THE UNITED STATES GOVERNMENT AND FEDERAL LAW IN THE MATTER OF VEHICLE STANDARDS.  See Note 2

THAT SAID, PLEASE BELIEVE THAT NO STATE OR MUNICIPALITY IS ABLE TO "OUTLAW" THE USE OF HEADLIGHT MODULATORS ON MOTORCYCLES.  THEY ARE LEGAL IN ALL 50 STATES IN THE UNITED STATES OF AMERICA.  THE CANADIAN GOVERNMENT ALSO PASSED A LAW PERMITTING HEADLIGHT MODULATOR USE ON MOTORCYCLES IN THE SPRING OF 2000, SO THEIR USE IS ALSO PERMITTED NORTH OF THE U.S. BORDER.


THE CODE:

The text of paragraph S7.9.4 reads as follows:

S7.9.4 Motorcycle headlamp modulation system

S7.9.4.1 A headlamp on a motorcycle may be wired to modulate either the upper beam or the lower beam from its maximum intensity to a lesser intensity provided that:

(a) The rate of modulation shall be 240 plus-or-minus 40 cycles per minute.

(b) The headlamp shall be operated at maximum power for 50 to 70 percent of each cycle.

(c) The lowest intensity at any test point shall not be less than 17 percent of the maximum intensity measured at the same point.

(d) The modulator switch shall be wired in the power lead of the beam filament being modulated and not in the ground side of the circuit.

(e) Means shall be provided so that both the lower beam and upper beam remain operable in the event of a modulator failure.

(f) The system shall include a sensor mounted with the axis of its sensing element perpendicular to a horizontal plane. Headlamp modulation shall cease whenever the level of light emitted by a tungsten filament light operating at 3000 degrees Kelvin is either less than 270 lux (25 foot-candles) of direct light for upward pointing sensors or less than 60 lux (5.6 foot-candles) of reflected light for downward pointing sensors. This light is measured by a silicon cell type light meter that is located at the sensor and pointing in the same direction as the sensor. A Kodak Gray Card (Kodak R-27) is placed at ground level to simulate the road surface in testing downward pointing sensors.

(g) When tested in accordance with the test profile shown in Figure 9, the voltage drop across the modulator when the lamp is on at all test conditions for 12 volt systems and 6 volt systems shall not be greater than .45 volt. The modulator shall meet all of the provisions of the standard after completion of the test profile shown in Figure 9.

(h) Means shall be provided so that both the lower and upper beam function at design voltage when the headlamp control switch is in either the lower or upper beam position when the modulator is off.

S7.9.4.2

(a) Each motorcycle headlamp modulator not intended as original equipment, or its container, shall be labeled with the maximum wattage, and the minimum wattage appropriate for its use. Additionally, each such modulator shall comply with S7.9.4.1 (a) through (g) when connected to a headlamp of the maximum rated power and a headlamp of the minimum rated power, and shall provide means so that the modulated beam functions at design voltage when the modulator is off.

(b) Instructions, with a diagram, shall be provided for mounting the light sensor including location on the motorcycle, distance above the road surface, and orientation with respect to the light.


EPILOG:

IF YOU HAVE A HEADLIGHT MODULATOR INSTALLED, AND HAVE NO OTHER PROOF OF ITS LEGALITY, I SUGGEST YOU PRINT ONE OR MORE COPIES OF TEXT FROM THIS WEB PAGE AND KEEP IT WITH YOU, WITH YOUR OTHER CYCLE PAPERWORK (REGISTRATION, INSURANCE CARD, ETC.). IT CAN THEN BE RETRIEVED QUICKLY IN THE EVENT THAT YOU ARE STOPPED AND HAVE NO OTHER ACCESS TO THE CODE OF FEDERAL REGULATIONS TO PROVE ITS LEGALITY.

ALTHOUGH THERE IS SOME EDITORIAL CONTENT ON THIS PAGE, THE SAFETY STANDARD (LAW) IS STATED VERBATIM FROM THE CODE OF FEDERAL REGULATIONS AND CAN BE VERIFIED AND VALIDATED BY ANY LAW ENFORCEMENT OFFICER OR COMPETENT ATTORNEY.


          NOTE 1         

Selected excerpts from the Hurt Study** supporting use of a Headlamp Modulator:

In multiple vehicle accidents, the driver of the other vehicle violated the motorcycle right-of-way and caused the accident in two-thirds of those accidents.

The failure of motorists to detect and recognize motorcycles in traffic is the predominating cause of motorcycle accidents. The driver of the other vehicle involved in collision with the motorcycle did not see the motorcycle before the collision, or did not see the motorcycle until too late to avoid the collision.

Intersections are the most likely place for the motorcycle accident, with the other vehicle violating the motorcycle right-of-way, and often violating traffic controls.

Conspicuity of the motorcycle is a critical factor in the multiple vehicle accidents, and accident involvement is significantly reduced by the use of motorcycle headlamps (on in daylight) and the wearing of high visibility yellow, orange or bright red jackets.

The typical motorcycle pre-crash lines-of-sight to the traffic hazard portray no contribution of the limits of peripheral vision; more than three-fourths of all accident hazards are within 45deg of either side of straight ahead.

Conspicuity of the motorcycle is most critical for the frontal surfaces of the motorcycle and rider.

Any effect of motorcycle color on accident involvement is not determinable from these data, but is expected to be insignificant because the frontal surfaces are most often presented to the other vehicle involved in the collision.

Motorcycles equipped with fairings and windshields are underrepresented in accidents, most likely because of the contribution to conspicuity and the association with more experienced and trained riders.

** Motorcycle Accident Cause Factors and Identification of Countermeasures, Volume 1: Technical Report, Hurt, H.H., Ouellet, J.V. and Thom, D.R., Traffic Safety Center, University of Southern California, Los Angeles, California 90007, Contract No. DOT HS-5-01160, January 1981 (Final Report)


          NOTE 2         

Here is a copy of the relevant section of Title 49, United States Code, Chapter 301 Motor Vehicle Safety.  This law prohibits states from forbidding a system that complies with FMVSS 108 The full document can be found at this link.

TITLE 49, UNITED STATES CODE CHAPTER 301 MOTOR VEHICLE SAFETY

SUBCHAPTER I GENERAL 
Sec. 30101. Purpose and policy. 
Sec. 30102. Definitions. 
Sec. 30103. Relationship to other laws. 

UNIFORMITY OF REGULATIONS

The Secretary of Transportation may not prescribe a safety regulation related to a motor vehicle subject to subchapter II of chapter 105 of this title that differs from a motor vehicle safety standard prescribed under this chapter. However, the Secretary may prescribe, for a motor vehicle operated by a carrier subject to subchapter II of chapter 105, a safety regulation that imposes a higher standard of performance after manufacture than that required by an applicable standard in effect at the time of manufacture.

PREEMPTION

When a motor vehicle safety standard is in effect under this chapter, a State or a political subdivision of a State may prescribe or continue in effect a standard applicable to the same aspect of performance of a motor vehicle or motor vehicle equipment only if the standard is identical to the standard prescribed under this chapter. However, the United States Government, a State, or a political subdivision of a State may prescribe a standard for a motor vehicle or motor vehicle equipment obtained for its own use that imposes a higher performance requirement than that required by the otherwise applicable standard under this chapter.

A State may enforce a standard that is identical to a standard prescribed under this chapter.

ANTITRUST LAWS This chapter does not exempt from the antitrust laws conduct that is unlawful under those laws; or prohibit under the antitrust laws conduct that is lawful under those laws.

WARRANTY OBLIGATIONS AND ADDITIONAL LEGAL RIGHTS AND REMEDIES Sections 30117(b), 30118-30121, 30166(f), and 30167(a) and (b) of this title do not establish or affect a warranty obligation under a law of the United States or a State. A remedy under those sections and sections 30161 and 30162 of this title is in addition to other rights and remedies under other laws of the United States or a State.

COMMON LAW LIABILITY Compliance with a motor vehicle safety standard prescribed under this chapter does not exempt a person from liability at common law.


          ADDENDUM ~ 2012         

As noted from the Hurt Report:

"Conspicuity of the motorcycle is a critical factor in the multiple vehicle accidents, and accident involvement is significantly reduced by the use of motorcycle headlamps (on in daylight) and the wearing of high visibility yellow, orange or bright red jackets."

Improvements in conspicuity are now mandated for all motorcyclists on military property.  The popularity of motorcycles among military service members is significant, and especially for those returning from Iraq and Afghanistan following their lengthy deployments.  Many returning soldiers and marines have bought new motorcycles upon their return and suffer from diminished riding skills also as a result from being away for so long.  Improving their survival rate on bases is paramount.  Making sure they're more visible is a great help.

Either Hi-Vis (also spelled hi-viz) Neon Yellow or "Blaze" Bright Orange vests meeting Military Specifications are required for all riders entering a military base, whether on active duty, in the reserves, or as a member of the civilian populace.  Note that hi-vis neon yellow (sometimes called lime) vests are also required for all road workers on federally-funded highways. 

Hi-vis yellow is the only color not duplicated in nature, making it contrast with any background.

More and more "street riders" have found the improvement in their visibility to others (and especially distracted drivers) beneficial by wearing a conspicuity vest or jacket at all times.  More and more manufacturers of cycling garb are offering their lines of clothing in highly visible colors as well.  Olympia Motorsports offers a great line of Hi-Vis jackets and vests for motorcyclists.

Going away are the days of "invisible" black leather jackets for riders, yielding to armored textile jackets and vests in bright colors.  Modern-day textile clothing offers as much -- or more -- protection to the rider who goes down in an accident.

 

H A P P Y     M O D U L A T I N G !