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WHAT'S NEW
September 2008
“I’m going to buy a new helmet,
What’s a good motorcycle helmet?”
This is a question often asked of HPRL staff members, and there are both long
and short answers to the question. We like the long answers because the
selection of a helmet for yourself, or a close friend, can be an event that has
a good result, or a serious consequence. Fortunately for the public, with the US
DOT enforcing the Federal Motor Vehicle Safety Standard No. 218, practically any
choice will provide the head protection required in motorcycle operation. Also
with many different standards in effect for motorcycle helmets, accident
research in the USA has shown that the great variety of motorcycle crashes does
not favor any other standard if the helmet does in fact qualify for that FMVSS
No. 218, aka the “DOT” standard.
The “DOT” standard has many important requirements of labeling, penetration
resistance, impact attenuation, retention system strength, etc, and any helmet
offered for sale in the USA must meet this standard, and DOT continually picks
up helmets from the marketplace and tests these helmets to insure the standards
are maintained. Of course, it is attractive to have a helmet that meets a dozen
different standards but only one standard is important, “DOT” is the law of the
USA and any helmet must meet this standard without question. The compliance with
any other standard does not necessarily make the helmet perform better in
accidents. Any impact test more severe than the DOT test simply requires a
stronger shell and stiffer liner, which will not necessarily provide better
impact attenuation in typical motorcycle accidents. In fact it can aggravate
diffuse brain injury.
The DOT standard has one part of the impact attenuation tests where the helmet
is impacted onto a flat steel anvil from a drop height of 6ft, or an impact
speed of 13.4mph. Two successive test impacts are made in four different
environmental conditions to simulate wet, hot and cold helmets on this flat
anvil as well as other impact conditions. The test impact velocity of 13.4mph
may seem to be too low to represent a motorcycle crash but accident research
shows that this includes 90 to 95% of all head impacts in motorcycle accidents.
A typical motorcycle accident has the motorcycle crashing into the right front
side of a left-turning automobile, with the rider vaulting over the hood and
landing on the pavement to hit their helmeted head from a fall of about 6ft,
just like the 6ft flat anvil drop test of the DOT standard! Since the DOT test
requires attenuation of that impact so that no injurious impact is transmitted
to the brain, the rider may have other leg, chest, etc. injuries, the DOT
qualified helmet has prevented any permanent head injuries.
The first step in helmet selection is look for the “DOT” label on the back of
the helmet. In addition, the other labeling on the helmet should identify the
manufacturer, date of manufacture, materials used in making the shell and liner,
size, care of the helmet, etc. It is always a good idea to look up the
manufacturer and see if any of the helmets have flunked the DOT testing, but DOT
is very often slow in catching up with the bad guys. There many different
manufacturers and many good names have been around for a long time, e.g., Bell,
Shoei, Arai, HJC, KBC, etc. and those durable names are associated with durable
helmets.
There are three different styles of helmets: partial coverage, full coverage and
full facial coverage with chin bar. If the rider is really serious about
protection, more coverage gives more protection and the full facial coverage
helmet offers the most protection. The full facial coverage helmet with chin bar
and a face shield covers and protects as mush as you can get and the partial
coverage helmet covers and protects only the minimum area specified by the
standard. Of course comfort on a hot day in slow moving traffic brings sweat
galore in the full facial coverage helmet and cheers for the open,
well-ventilated partial coverage helmet. So the decision is often made
difficult: comfort vs. protection However the decision is simplified greatly by
considering that all helmets from the $70 special to the $900 deluxe helmet
“qualified to racing standards” have the very same basic impact protection
(because they have to meet the same DOT test requirements!).
Often riders will select a “novelty” helmet because the are lighter, less
expensive and a slick way of protesting mandatory helmet use laws, but also
inviting serious head injury because the novelty helmets do not qualify to the
DOT standard; the shell is weak and flexible and there is no energy absorbing
expanded polystyrene bead foam (EPS) liner for impact absorption.
What color is best? A lot of people like the black helmet but a black helmet is
just like a black car in summer, long time exposure to a hot sun will create a
lot of heat inside the black helmet compared to a white or silver helmet. So
light colors are cooler but also more conspicuous in traffic. Also your jacket
should be a light highly visible color because accident research shows that
riders with high visibility upper torso garments were the least involved in
accidents with other vehicles (so much for the inconspicuous black leather
jacket that protects so well in a crash!).
When you have decided on a style and color of helmet, trying on the helmet is
the final test. Get a snug but comfortable fit for the helmet, then fasten the
chin strap just as if you were going to wear it then and there. When all
fastened up, reach back to the rear edge of the helmet and see if you can pull
the helmet up and forward off your head. This is the way most helmets leave home
in a crash! They don’t fit close enough and the chinstrap is not tight enough
and when you get hit in a crash, the helmet rolls off forward and takes off like
it had wings. This is so critical for anybody concerned about a “bad hair day”
and accepts a looser helmet fit and a looser fastening of the chinstrap.
Whatever helmet you select, be sure that it will pass this forward roll-off
test.
Full facial coverage helmets are more likely to pass this test because the chin
bar hits the sternum and stops, but it will keep going unless the chinstrap is
secure. There should be no more than space for one (or maybe just two) finger
between the chin and chin strap. Of course, partial coverage helmets are more
mobile on the head than full or full facial coverage helmets, and a V-type
arrangement of front and rear straps is needed to stabilize the partial coverage
helmet and prevent roll-off
Don’t forget that eye protection against the wind blast is necessary to preserve
you vision. A full facial coverage helmet needs a good optical quality
polycarbonate face shield and a full or partial coverage helmet could snap on a
wrap- around shield of the same clear plastic protection for your vision.
HPRL tests many different brands of motorcycle helmets and it is difficult to
make a recommendation of a specific brand of motorcycle helmet, so any
recommendation is on the basis of actual recent testing. Our helmet testing
during the last five or six years has shown one brand of helmets to show
superior performance in DOT testing; Shoei helmets consistently show very low
impact response and the highest crash protection, especially for the full facial
coverage and modular helmets. For example the new Shoei VFX-W full facial
coverage helmet did not exceed 180g of the 400g limit in a recent series of DOT
testing. That is truly superior impact attenuation performance on the DOT tests.
So we recommend your consideration of any Shoei helmet (but especially the VFX-W)
as a suitable choice for protection in motorcycle riding
Hugh H. Hurt, Jr. PE
Professor Emeritus-USC
President, HPRL
29.07.08
November 2007
A New Book about
Helmets
Dr. Jim Newman has
completed his new book “Modern Sports Helmets, Their History, Science and Art,”
and it has been published by Schiffer. “Dr. J.” has sent HPRL an autographed
copy of this new volume and it is being read day and night by staff members. It
is a very complete record of the various sports helmets with detailed coverage
on the head protection used in motor sports with very complete sections covering
motorcycle and bicycle helmets. The sections of the book cover many aspects such
as design and construction, head injury biomechanics, helmet standards, etc.
with specific applications from the history of head protection development.
There are many excellent photographs describing the many stages of helmet
development and application in motor sports. The contribution of C. F. Lombard,
S. W. Ames and H. P. Roth at USC is recorded as the landmark development in the
science of head protection, and gives examples of the extension of the
application of the impact energy absorbing design to improved head protection.
Dr. J. is one of
the leading scientists in the field of head protection and has published a world
of research on that subject. He conducted one of the first studies of motorcycle
accidents in Canada in the 1970’s and helped to train the research team at USC
that conducted the DOT study of “Motorcycle Accident Cause Factors and
Identification of Countermeasures.” In addition, in that same period of time,
Dr. J. was a consultant at Bell Helmets in Long Beach developing the early
versions of Bell’s famous bicycle helmet, the “Biker.”
Of course, HPRL
recommends this book by Dr. J. as “THE BOOK” to have and read to fill your needs
for helmet knowledge. It has the whole story like never before presented by a
real scientific authority.
Harry Hurt, 19
November, 2007
August, 2007
Warning to Bicycle Helmet Users: During the last
two years, the technical staff of HPRL has encountered an interesting problem
with the aerodynamic-shaped or streamlined helmets. These popular helmets have a
teardrop design which tapers to a wedge at the rear of the helmet, supposedly
offering reduced aerodynamic drag along with increased ventilation through the
many openings in the shell.
The adverse effect of this aerodynamic shape is
that the wedge at the back of the helmet tends to deflect and rotate the helmet
on the head when impact occurs there. Any impact at the front or sides of the
streamlined helmet is not affected, but any impact at the rear wedge tends to
rotate the helmet on the head and possibly deflect the helmet exposing the bare
head to impact, or at worst ejecting the helmet completely from the head.
Actually, everybody who has tested these streamlined helmets over the years had
the problem of these helmets being displaced during impact testing at the rear
wedge, and usually additional tape was required to maintain the helmet in place
(the retention system alone could not keep the helmet in place during testing).
Unfortunately, the implication of helmet displacement and possible ejection in
an accident did not register previously as a real hazard, but accident cases are
showing this to be a real problem. Accident impacts at the rear of these
streamlined helmets can cause the helmet to rotate away and expose the head to
injury. The forces from the wedge effect can stretch the chin straps very easily
and break the Roc Loc (or equivalent).
This problem will be studied by HPRL technical
staff and presented to the ASTM F08 Committee for consideration. In the
meanwhile insure the chin straps of your helmet are securely fastened and
properly adjusted, and if you fall, do your best not to hit the wedge part of
the back of the helmet. Just take note that the Extreme BMX'rs who crash a lot
don't use many of the streamlined bike helmets.
August, 2004
HPRL Staff have prepared
and submitted two scientific papers to the international meeting of the Institut für Zweiradsicherheit. The subject is a comparison of the lower
extremities injuries from two major sets of motorcycle accident data, Thailand
and USC/DOT.
July, 2004
Jay W. Preston, CSP, PE, has joined the HPRL
Board of Directors. Preston is one of the most experienced safety engineers in
the USA, and is active in a variety of industrial safety activities and related
organizations. Preston is recognized as a genuine expert in all areas of
industrial safety and has consulted on behalf of practically every element of
industry, insurance and government.
July, 2004
HPRL is completing the
analysis and publication of 304 fatal motorcycle accident cases. Each case has a
special head and neck dissection procedure with full central system
neuropathology in addition to the whole body autopsy procedure. This publication
will present the finest possible detail of head and neck injuries to these
fatally injured motorcyclists, with the distinction between helmeted and unhelmeted victims. Unfortunately this project has languished for a long time
because further support from DOT/NHTSA was not available and industry has not
helped with the project. HPRL needs an angel to help with the cost of printing
and distributing this publication to the scientific community, about $25,000.
Any serious benefactor wishing to help with this project, please call
(562) 529-3295.
April, 2003
"Modular Helmets" is a new article by Art
Friedman in the April, 2003 issue of motorcycle CRUISER magazine. This new
article by Art Friedman reviews the tests of a group of new helmets at HPRL and
has all of the great facts about these popular helmets with the flip-up face
sections. Of course, one of the best ever complete articles about helmets also
written by Art Friedman was "Hard Headed?" in the August, 2000 issue of
motorcycle CRUISER magazine. These articles are worth your collection for the
good stuff about helmets.
Links to sites related to the work of HPRL:
Motorcycle Safety Foundation -
http://www.msf-usa.org
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PROTECTION RESEARCH LABORATORY