The "Hurt" Study
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: There was a study of similar
nature done in Europe of accidents over a 2 year period and published in
September, 2004: It si called the MAIDS report.
Click here to access a PDF file
of the report. Lots of detail - and someday I will try to summarize
it down - until then, look at the executive summary, and then dive into
Note: Fatal Accident Analysis by NHTSA:
NHTSA Motorcycle Fatalities: 1990-99
(Conclusions Pg 4 & More Detail Pg 35)
Another Note: Plans are underway to
conduct a similar study in the US. Funding was/is included in the
latest Highway funding bill. Use of the funding is tied to the
Motocycle Industry and Community coming up with a level of matching
funding. Visit the AMA site for details and to make a small
donation - to make sure this tudy gets done!
The Hurt study, published in 1981, was a ground-breaking
report on the causes and effects of motorcycle accidents. Although more
than 15 years old at this time, the study still offers riders insight into
the statistics regarding motorcycle accidents and tips on safer riding.
With funds from the National Highway Traffic Safety Administration,
researcher Harry Hurt (from which the study gets its common name) of the
University of Southern California, investigated almost every aspect of 900
motorcycle accidents in the Los Angeles area. Additionally, Hurt and his
staff analyzed 3,600 motorcycle traffic accident reports in the same
This is the same study that is frequently quoted in the
MSF rider safety courses.
A complete non-summarized version of this document is
available from the National Technical Information Service (NTIS) by
ordering document number PB81-206443/LL. The cost is $84.00 each per
document plus $5.00 handling per order. For more information, call the
NTIS Sales Desk at 1-800-553-NTIS or 1-703-605-6000.
Summary of Findings
accident and exposure data there are special observations which relate to
accident and injury causation and characteristics of the motorcycle
accidents studied. These findings are summarized as follows:
- Approximately three-fourths of these motorcycle
accidents involved collision with another vehicle, which was most
usually a passenger automobile.
- Approximately one-fourth of these motorcycle
accidents were single vehicle accidents involving the motorcycle
colliding with the roadway or some fixed object in the environment.
- Vehicle failure accounted for less than 3% of these
motorcycle accidents, and most of those were single vehicle accidents
where control was lost due to a puncture flat.
- In the single vehicle accidents, motorcycle rider
error was present as the accident precipitating factor in about
two-thirds of the cases, with the typical error being a slideout and
fall due to overbraking or running wide on a curve due to excess speed
- Roadway defects (pavement ridges, potholes, etc.)
were the accident cause in 2% of the accidents; animal involvement was
1% of the accidents.
- In the 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.
- Deliberate hostile action by a motorist against a
motorcycle rider is a rare accident cause. The most frequent accident
configuration is the motorcycle proceeding straight then the automobile
makes a left turn in front of the oncoming motorcycle.
- 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.
- Weather is not a factor in 98% of motorcycle
- Most motorcycle accidents involve a short trip
associated with shopping, errands, friends, entertainment or recreation,
and the accident is likely to happen in a very short time close to the
- The view of the motorcycle or the other vehicle
involved in the accident is limited by glare or obstructed by other
vehicles in almost half of the multiple vehicle accidents.
- 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
- Fuel system leaks and spills were present in 62% of
the motorcycle accidents in the post-crash phase. This represents an
undue hazard for fire.
- The median pre-crash speed was 29.8 mph, and the
median crash speed was 21.5 mph, and the one-in-a-thousand crash speed
is approximately 86 mph.
- 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.
- Vehicle defects related to accident causation are
rare and likely to be due to deficient or defective maintenance.
- Motorcycle riders between the ages of 16 and 24 are
significantly overrepresented in accidents; motorcycle riders between
the ages of 30 and 50 are significantly underrepresented. Although the
majority of the accident-involved motorcycle riders are male (96%), the
female motorcycles riders are significantly overrepresented in the
- Craftsmen, laborers, and students comprise most of
the accident-involved motorcycle riders. Professionals, sales workers,
and craftsmen are underrepresented and laborers, students and unemployed
are overrepresented in the accidents.
- Motorcycle riders with previous recent traffic
citations and accidents are overrepresented in the accident data.
- The motorcycle riders involved in accidents are
essentially without training; 92% were self-taught or learned from
family or friends. Motorcycle rider training experience reduces accident
involvement and is related to reduced injuries in the event of
- More than half of the accident-involved motorcycle
riders had less than 5 months experience on the accident motorcycle,
although the total street riding experience was almost 3 years.
Motorcycle riders with dirt bike experience are significantly
underrepresented in the accident data.
- Lack of attention to the driving task is a common
factor for the motorcyclist in an accident.
- Almost half of the fatal accidents show alcohol
- Motorcycle riders in these accidents showed
significant collision avoidance problems. Most riders would overbrake
and skid the rear wheel, and underbrake the front wheel greatly reducing
collision avoidance deceleration. The ability to countersteer and swerve
was essentially absent.
- The typical motorcycle accident allows the
motorcyclist just less than 2 seconds to complete all collision
- Passenger-carrying motorcycles are not
overrepresented in the accident area.
- The driver of the other vehicles involved in
collision with the motorcycle are not distinguished from other accident
populations except that the ages of 20 to 29, and beyond 65 are
overrepresented. Also, these drivers are generally unfamiliar with
- The large displacement motorcycles are
underrepresented in accidents but they are associated with higher injury
severity when involved in accidents.
- 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 riders in these accidents were
significantly without motorcycle license, without any license, or with
- Motorcycle modifications such as those associated
with the semi-chopper or cafe racer are definitely overrepresented in
- The likelihood of injury is extremely high in these
motorcycle accidents-98% of the multiple vehicle collisions and 96% of
the single vehicle accidents resulted in some kind of injury to the
motorcycle rider; 45% resulted in more than a minor injury.
- Half of the injuries to the somatic regions were to
the ankle-foot, lower leg, knee, and thigh-upper leg.
- Crash bars are not an effective injury
countermeasure; the reduction of injury to the ankle-foot is balanced by
increase of injury to the thigh-upper leg, knee, and lower leg.
- The use of heavy boots, jacket, gloves, etc., is
effective in preventing or reducing abrasions and lacerations, which are
frequent but rarely severe injuries.
- Groin injuries were sustained by the motorcyclist in
at least 13% of the accidents, which typified by multiple vehicle
collision in frontal impact at higher than average speed.
- Injury severity increases with speed, alcohol
involvement and motorcycle size.
- Seventy-three percent of the accident-involved
motorcycle riders used no eye protection, and it is likely that the wind
on the unprotected eyes contributed in impairment of vision which
delayed hazard detection.
- Approximately 50% of the motorcycle riders in traffic
were using safety helmets but only 40% of the accident-involved
motorcycle riders were wearing helmets at the time of the accident.
- Voluntary safety helmet use by those
accident-involved motorcycle riders was lowest for untrained,
uneducated, young motorcycle riders on hot days and short trips.
- The most deadly injuries to the accident victims were
injuries to the chest and head.
- The use of the safety helmet is the single critical
factor in the prevention of reduction of head injury; the safety helmet
which complies with FMVSS 218 is a significantly effective injury
- Safety helmet use caused no attenuation of critical
traffic sounds, no limitation of precrash visual field, and no fatigue
or loss of attention; no element of accident causation was related to
- FMVSS 218 provides a high level of protection in
traffic accidents, and needs modification only to increase coverage at
the back of the head and demonstrate impact protection of the front of
full facial coverage helmets, and insure all adult sizes for traffic use
are covered by the standard.
- Helmeted riders and passengers showed significantly
lower head and neck injury for all types of injury, at all levels of
- The increased coverage of the full facial coverage
helmet increases protection, and significantly reduces face injuries.
- There is not liability for neck injury by wearing a
safety helmet; helmeted riders had less neck injuries than unhelmeted
riders. Only four minor injuries were attributable to helmet use, and in
each case the helmet prevented possible critical or fatal head injury.
- Sixty percent of the motorcyclists were not wearing
safety helmets at the time of the accident. Of this group, 26% said they
did not wear helmets because they were uncomfortable and inconvenient,
and 53% simply had no expectation of accident involvement.
- Valid motorcycle exposure data can be obtained only
from collection at the traffic site. Motor vehicle or driver license
data presents information which is completely unrelated to actual use.
- Less than 10% of the motorcycle riders involved in
these accidents had insurance of any kind to provide medical care or