Bus Crashworthiness
Schoolbus Accidents and Occupant Protection Systems
Disclaimer: Simulations presented below used scene and geological surveys, highway design plans, witness statements, vehicle testing, vehicle plans and vehicle operating characteristics. The depictions represent actual lighting and weather conditions at the time of the accident
Videos are available in either MPEG-1 or RealVideo, and were presented at the Board meeting on 9/21/99 in Washington, D.C., for the Special Investigation Report on Bus Crashworthiness.
Two animated views of the vehicle dynamics of each accident are shown and several views of occupant kinematics unrestrained and restrained with lap belts and lap belts and shoulder belts are also shown. Slides showing the predicted injuries and accident vehicles are also presented. The schoolbus accidents are:
1) Monticello, Minnesota, April 10, 1997
MonticelloCrash.mpv
(Video = 658K)
Overhead zoom view of the bus and truck approaching the intersection
and the crash
This view displays the approach of both vehicles to the
intersection, the crash and the vehicles' trajectory after impact. The
truck is approaching the intersection at 55 mph, slows to 53 mph, brakes
and slows to about 49 mph at impact. The truck goes past a "STOP"
sign. The bus accelerates from 46 to 50 mph at impact.
MonticelloSlow.mpv
(Video = 1,418K)
Monticello, MN - Overhead Slow motion view of the bus and truck crash
This view displays the crash and the vehicles' initial
trajectory after impact. The truck is traveling at 49 mph at impact. The
bus accelerates to 50 mph at impact.
Monticello_unrest.rm
(Video = 486K)
Overhead view of the unrestrained occupant kinematics (1/10th speed)
This view displays the occupant kinematics for the six
occupants located in the last three rows of the school bus. Head injuries
were predicted for the three occupants initially seated along the driver's
sidewall.
Monticello2pb_ind.rm
(Video = 271K)
Monticello, MN - Overhead view of the lap belt restrained occupant kinematics
(1/10th speed)
This view displays the lap belted occupant kinematics
for the six occupants located in the last three rows of the school bus.
Head injuries were predicted for four of the simulated occupants.
Monticello3pb_ind.rm
(Video = 280K)
Monticello, MN - Overhead view of the lap/shoulder belt restrained occupant
kinematics (1/10th speed)
This view displays the lap/shoulder belted occupant kinematics
for the six occupants located in the last three rows of the school bus.
Head injuries were predicted for five of the simulated occupants.
Predicted
Head Injuries
This slide illustrates the predicted head injuries
in the Monticello, MN simulation for each of the three restraint conditions:
unrestrained, lap belt restrained, and lap/shoulder belt restrained. The
yellow X indicates the occupant predicted to sustain a head injury. Three
head injuries were predicted for the unrestrained occupants, four for the
lap belt restrained occupants and five for the lap/shoulder belt restrained
occupants.
Predicted Chest Injuries
This slide illustrates the predicted chest injuries
in the Monticello, MN simulation for each of the three restraint conditions:
unrestrained, lap belt restrained, and lap/shoulder belt restrained. The
yellow X indicates the occupant predicted to sustain a chest injury. Four
chest injuries were predicted for the unrestrained occupants, four for
the lap belt restrained occupants and three for the lap/shoulder belt restrained
occupants.
Predicted
Neck Injuries
This slide illustrates the predicted neck injuries
in the Monticello, MN simulation for each of the three restraint conditions:
unrestrained, lap belt restrained, and lap/shoulder belt restrained. The
yellow X indicates the occupant predicted to sustain a neck injury. Neck
injuries were not investigated for the unrestrained occupants because the
appropriate simulated dummy was not available at the time. Three neck injuries
were predicted for the lap belt restrained occupants and two for the lap/shoulder
belt restrained occupants.
2) Holyoke, Colorado, September 1, 1998
HolyokeChase.mpv
(1,069K)
Overhead Chase view of the truck as it approaches the schoolbus from
behind
This view displays the truck as it approaches the stopped
bus that begins to accelerate. The truck is travelling 60 mph, brakes and
slows to 50 mph at impact as it turns left. The stopped bus accelerates
to about 5 mph.
HolyokeFront.mpv
(584K)
View from in front of the crash as the truck hits the bus
This view displays the crash from in front of the bus
as the truck strikes the bus, the bus spins and rolls over.
Holyoke_standing.rm
(532K)
Overhead view of the unrestrained occupant kinematics (1/10th speed)
with the two ejected occupants standing in the aisle
This view displays the occupant kinematics for the four
occupants located in the last two rows of the school bus. Passenger reports
were unclear whether the two ejected passengers were seated at the time
of impact. Many simulations were performed to look at the potential ejection
paths and to replicate the final rest positions of these two occupants.
Head injuries were predicted for the two ejected occupants.
Holyoke_unrest.rm
(486K)
Overhead view of the unrestrained occupant kinematics (1/10th speed)
with the two ejected occupants seated
This view displays the occupant kinematics for the four
occupants located in the last two rows of the school bus. Passenger reports
were unclear whether the two ejected passengers were seated at the time
of impact. This simulation shows all occupants seated within the compartment.
A single head injury was predicted as one occupant's head contacted the
sidewall during the overturn sequence.
Holyoke2pb_ind.rm
(545k)
Overhead view of the lap belt restrained occupant kinematics (1/10th
speed)
This view shows the lap belt restrained occupant kinematics
for the four occupants located in the last two rows of the bus. Head injuries
were not predicted for these simulated occupants.
Holyoke3pb_ind.rm
(538k)
Overhead view of the lap/shoulder belt restrained occupant kinematics
(1/10th speed)
This view shows the lap/shoulder belt restrained occupant
kinematics for the four occupants located in the last two rows of the bus.
Head injuries were not predicted for these simulated occupants.
Predicted
Head Injuries
This slide illustrates the predicted head injuries
in the Holyoke, CO simulation for the unrestrained condition with the two
ejected occupants standing in the aisle. The yellow X indicates the occupant
predicted to sustain a head injury. Three head injuries were predicted
for the unrestrained occupants. Two head injuries were predicted for the
ejected occupants while the final head injury was predicted when the occupant
on the opposite side interacted with the two ejected occupants. When seated
within the seating compartment either restrained or not restrained, the
occupants were not ejected and the predicted injuries were reduced. Chest
and neck injuries were also investigated but were not presented graphically.
3) Holmdel, New Jersey, September 18, 1998
HolmdelBusChase.mpv
(1.06M)
Chase View from behind the bus as the bus approaches the intersection
and crashes. The speed of the bus is 22 mph as it approaches
the intersection and it slows to 21 mph at impact. The speed of the truck
on the approach was 41 mph and it slowed to about 39 mph at impact with
the bus.
HolmdelDynamicsView.mpv
(655K)
A close-up view of the Holmdel crash and the vehicle dynamics.
This view shows the impact, bus deformation, vehicle
separation, overturn of the truck onto the bus and a portion of the vehicles'
slide to their final resting positions.
HolmdelSideways20.mpv
(702K)
Holmdel, NJ - Overhead view of the unrestrained occupant kinematics
(1/20th speed)
This view shows the unrestrained occupant kinematics
for the four occupants located in the first two rows of the bus. The occupant
in seat 1A is positioned sideways, representing the passenger's statements.
A head injury was predicted for the occupant in the upper right side of
the video corresponding to the actual head injury sustained by that bus
passenger.
HolmdelForward20.mpv
(702K)
Overhead view of the unrestrained occupant kinematics (1/20th speed)
This view shows the unrestrained occupant kinematics
for the four occupants located in the first two rows of the bus. The occupant
in seat 1A is positioned forward to enable comparisons to the restrained
conditions. Two head injuries were predicted for the occupants in the first
row of seats.
Holmdel2pb.mpv
(559K)
Overhead view of the lap belt restrained occupant kinematics (1/20th
speed)
This view shows the lap belt restrained occupant kinematics
for the four occupants located in the first two rows of the bus. Head injuries
were predicted for all four occupants.
Holmdel3pb.mpv
(559K)
Overhead view of the lap/shoulder belt restrained occupant kinematics
(1/20th speed)
This view shows the lap/shoulder belt restrained occupant
kinematics for the four occupants located in the first two rows of the
bus. Head injuries were predicted for the two occupants seated along the
driver's side (left side on the video).
Predicted Head Injuries
This slide illustrates the predicted head injuries
in the Holmdel, NJ simulation for each of the three restraint conditions:
unrestrained, lap belt restrained, and lap/shoulder belt restrained. The
yellow X indicates the occupant predicted to sustain a head injury. One
head injury was predicted for the unrestrained occupants, four for the
lap belt restrained occupants and two for the lap/shoulder belt restrained
occupants. Chest and neck injuries were also investigated but were not
presented graphically.
4) Other Accidents
The simulations were produced on an HVEtm system using m-smac (McHenry Software,Inc.), ReadDataFiles and GATB (Collision Engineering Associates, Inc.), MADYMO (developed in conjunction with a NHTSA contractor), EDSMACtm EDVDStm, EDVSMtm and EDGENtm programs. All of the programs starting with "ED" are trademarks of the Engineering Dynamics Corporation.
