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 geographic area.
Approximately three-fourths of these motorcycle accidents involved
collision with another vehicle, which was most usually a passenger
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 slide-out and fall due to over-braking or running wide
on a curve due to excess speed or under-cornering.
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
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
Weather is not a factor in 98% of motorcycle accidents.
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 trip origin.
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 red jackets.
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
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 accident data.
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 accidents.
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 involvement.
Motorcycle riders in these accidents showed significant collision
avoidance problems. Most riders would over-brake and skid the rear wheel, and
under-brake 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 avoidance action.
Passenger-carrying motorcycles are not overrepresented in the accident
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 motorcycles.
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
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 license revoked.
Motorcycle modifications such as those associated with the semi-chopper or
cafe racer are definitely overrepresented in accidents.
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
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
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 countermeasure.
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 helmet use.
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 injury severity.
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 replace property.