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
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
- 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
The flickering of the high-beam is unmistakable.
Disliked by some, misunderstood by many, it
by all. Simply put,
MODULATORS GET YOU NOTICED !
And being noticed improves the odds that you'll be
an inattentive driver, ergo the chance for a collision with an auto is
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!
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.
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?
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
2. Won't my
headlight bulb burn out from all that flickering?
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?
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
Headlight Modulator Etiquette:
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:
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
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.
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.
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.)
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 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.
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
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.
The text of
paragraph S7.9.4 reads as follows:
S7.9.4 Motorcycle headlamp
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.
headlamp shall be operated at maximum power for 50 to 70 percent of each
(c) The lowest
intensity at any test point shall not be less than 17 percent of the maximum
intensity measured at the same point.
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.
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 S18.104.22.168 (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.
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.
excerpts from the Hurt Study** supporting use of a Headlamp Modulator:
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
Intersections are the most likely place for the motorcycle accident, with the
other vehicle violating the motorcycle right-of-way, and often violating
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
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.
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)
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
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.
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
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
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
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.