1 Rollovers & Seatbelts Rollovers & Seatbelts Rollovers Rollovers & Seatbelts & Seatbelts
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Rollovers & SeatbeltsRollovers & Seatbelts
RolloversRollovers
& Seatbelts& Seatbelts
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Rollovers & SeatbeltsRollovers & Seatbelts
What is a “ROLLOVER”?What is a “ROLLOVER”?
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Rollovers & SeatbeltsRollovers & Seatbelts
What is a “ROLLOVER”?What is a “ROLLOVER”?
• a single vehicle incidenta single vehicle incident• vehicle “rolls” 90 deg or morevehicle “rolls” 90 deg or more
• ““driver looses control”driver looses control”
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Rollovers & SeatbeltsRollovers & Seatbelts
Does PDO have manyDoes PDO have many
““ROLLOVERS”?ROLLOVERS”?
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Rollovers & SeatbeltsRollovers & Seatbelts
PDO: many rollovers every year!PDO: many rollovers every year!
20002000 20012001 20022002 20032003 20042004 20052005 20062006 2007 td2007 td
RolloversRollovers 4343 3333 2222 2222 2121 4545 5454 4545
Km Km 118118 123 123 133133 139 139 145 145 151 151 161 161 175 175
RolloversRollovers
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Rollovers & SeatbeltsRollovers & Seatbelts
19-Oct-2007: on the way to Bahja
Driver: seatbelt – minor injuryPassenger: Seatbelt – minor injuryPassenger: NO seatbelt - DEAD
Rollover !!Rollover !!
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Rollovers & SeatbeltsRollovers & Seatbelts
9-Sept-2007: on the way to Haima
Driver: NO seatbelt - DEADPassenger: NO seatbelt - DEADPassenger: Seatbelt – minor injury
Rollover !!Rollover !!
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Rollovers & SeatbeltsRollovers & Seatbelts
2-Aug-2007: Qarn Alam Driver died – no seatbelt – head crushed under vehicle
Rollover !!Rollover !!
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Rollovers & SeatbeltsRollovers & Seatbelts23-Oct-2006
Marmul-Thumrait 7 km before Harweel junction
Driver: 39 yrs old, diedSpeed: at least 140 km/hr
PDO Spec vehicle: tampered!Seatbelt did not help anymore
Rollover !!Rollover !!
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Rollovers & SeatbeltsRollovers & Seatbelts
March/2001 March/2001
Maqbool Maqbool & &
Faisal Faisal DiedDied
Anything that goes wrong Anything that goes wrong at high SPEED is a BIG problem!!at high SPEED is a BIG problem!!
150 km/hr150 km/hr
TyreTyreblewblew
Rollover !!Rollover !!
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Rollovers & SeatbeltsRollovers & Seatbelts
30/Oct/01 LTI 30/Oct/01 LTI Permanent Total DisabilityPermanent Total Disability
Veered off to the rightVeered off to the rightOvercorrected, rolled 4xOvercorrected, rolled 4xClassic S patternClassic S patternNO rollover barNO rollover bar
Straight blacktop Fahud-NahadaStraight blacktop Fahud-Nahada
Rollover !!Rollover !!
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Rollovers & SeatbeltsRollovers & Seatbelts
Rollover !Rollover !
!!
Blacktop road Fahud- NizwaBlacktop road Fahud- Nizwa
Car moved right at high Car moved right at high speed. Driver over corrected speed. Driver over corrected and got into an S pattern:and got into an S pattern:Rolled & Flipped.Rolled & Flipped.
20/Nov/01 Fatality & LTI20/Nov/01 Fatality & LTI
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Rollovers & SeatbeltsRollovers & Seatbelts
2 man came out alive. 2 man came out alive. They were wearing their They were wearing their seatbelts. seatbelts.
1 man DIED. He was 1 man DIED. He was NOT wearing his NOT wearing his seatbeltseatbelt
NO SeatbeltNO Seatbelt= DEATH= DEATH
Nimr to Muscat 13th June 98Nimr to Muscat 13th June 98
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Rollovers & SeatbeltsRollovers & Seatbelts
What would you “prefer”?What would you “prefer”?
a Rollovera Rolloveroror
a Head on Collisiona Head on Collision
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Rollovers & SeatbeltsRollovers & Seatbelts
Rollovers are killers!Rollovers are killers!
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
Co
llis
ion
Co
llis
ion
wit
hF
ixed
Ob
ject
Ro
llo
ver
Ru
n-o
ver
(ped
estr
ian
)
Ru
n-o
ver
(an
imal
)
Traffic accidents breakdown per type in 1999/2004
2004 2003 20022001 2000 1999
0
50
100
150
200
250
Co
llis
ion
Co
llis
ion
wit
h F
ixed
Ob
ject
Ro
llo
ver
Ru
n-o
ver
(ped
estr
ian
)
Ru
n-o
ver
(an
imal
)
Fatalities per accident type 1999/2004
2004 2003 20022001 2000 1999
No of accidents No of death
Video 1Video 2
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Rollovers & SeatbeltsRollovers & Seatbelts
Common features of rollovers:Common features of rollovers:
• Speed (80 km/hr can be too fast !!)Speed (80 km/hr can be too fast !!)
• Mostly 4 WD (high Mostly 4 WD (high CCentre entre oof f GGravity cars)ravity cars)
• Most on straight roadsMost on straight roads
• Most classic “S” curves Most classic “S” curves
• Many on blacktop roads at high speedMany on blacktop roads at high speed
• Few: tyre blow-out, junction/speedFew: tyre blow-out, junction/speed
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Rollovers & SeatbeltsRollovers & Seatbelts
Why does a vehicle roll ?Why does a vehicle roll ?
How many rolls will it do ?How many rolls will it do ?
Simply Physics !Simply Physics !
Understand the physicsUnderstand the physics
to understand the controls……to understand the controls……
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Rollovers & SeatbeltsRollovers & Seatbelts
We have a “vehicle at speed”: why does it roll?We have a “vehicle at speed”: why does it roll?
Gravity Force Gravity Force GF = M x g (= constant)GF = M x g (= constant)
MM = = mass (kg)mass (kg)vv = = speed (m/s)speed (m/s)gg = = gravitationalgravitational
accelerationacceleration
CCentre entre oof f GGravityravity
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Rollovers & SeatbeltsRollovers & Seatbelts
Why does it roll?.... Because of centrifugal force!Why does it roll?.... Because of centrifugal force!
Gravity Force Gravity Force GF = M x g (= constant)GF = M x g (= constant)
Centrifugal Force (CF)Centrifugal Force (CF)
MM = = mass (kg)mass (kg)vv = = speed (m/s)speed (m/s)r r = = turn radius (m) turn radius (m) gg = = gravitationalgravitational
accelerationacceleration
CCentre entre oof f GGravityravity
MvMv22 CF= CF= --------------
r r
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Rollovers & SeatbeltsRollovers & Seatbelts
Why does it roll?.... Because of centrifugal force!Why does it roll?.... Because of centrifugal force!
Gravity Force Gravity Force GF = M x g (= constant)GF = M x g (= constant)
Centrifugal Force (CF)Centrifugal Force (CF)
MM = = mass (kg)mass (kg)vv = = speed (m/s)speed (m/s)r r = = turn radius (m) turn radius (m) gg = = gravitationalgravitational
accelerationacceleration
CF increases with:CF increases with:- v higher (higher speed)- v higher (higher speed)- r smaller (sharper turn)- r smaller (sharper turn)
CCentre entre oof f GGravityravity
MvMv22 CF= CF= --------------
r r
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Rollovers & SeatbeltsRollovers & SeatbeltsWe have a “rolling vehicle at speed” We have a “rolling vehicle at speed”
How many rolls will it do ?How many rolls will it do ?
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Rollovers & SeatbeltsRollovers & SeatbeltsWe have a “rolling vehicle at speed” We have a “rolling vehicle at speed”
How many rolls will it do ?How many rolls will it do ?
Kinetic Energy: ½ MKinetic Energy: ½ Mvv22
This energy is dissipated during the rollsThis energy is dissipated during the rollsMore energy more rolls!More energy more rolls!
Energy goes up with the square of the speed!Energy goes up with the square of the speed!
MM = = mass mass (kg)(kg)
vv = = speed speed (m/s) (m/s)
Km/hr Energy in % of 100 km/hr80 64%100 100%120 144%140 196%
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Rollovers & SeatbeltsRollovers & Seatbelts
Next 4 slides:Next 4 slides:
- 2 RTA’s are shown2 RTA’s are shown
- they are almost the samethey are almost the same
- compare themcompare them
- see what the differences aresee what the differences are
- discuss why the outcome was differentdiscuss why the outcome was different
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Rollovers & SeatbeltsRollovers & Seatbelts
2 Black Top Roads2 Black Top Roads2 Cars driving2 Cars driving
140 km/hr140 km/hr 80 km/hr80 km/hr
25/2/200325/2/2003 14/3/200314/3/2003
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Rollovers & SeatbeltsRollovers & Seatbelts
2 Tires blown2 Tires blown
140 km/hr140 km/hr 80 km/hr80 km/hr
25/2/200325/2/2003 14/3/200314/3/2003
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Rollovers & SeatbeltsRollovers & Seatbelts
2 Rollovers2 Rollovers
140 km/hr140 km/hr80 km/hr80 km/hr
25/2/200325/2/2003 14/3/200314/3/2003
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Rollovers & SeatbeltsRollovers & Seatbelts
PassengerPassenger25 years old 25 years old (driver’s son)(driver’s son)
Very badly Very badly InjuredInjured
Will he ever Will he ever recover?recover?Driver:Driver: DeadDead
1 Dead1 Dead1 Badly Hurt1 Badly Hurt
Driver: Driver:
Minor Minor scratches scratches
and bruisesand bruises
No InjuryNo Injury
25/2/200325/2/2003 14/3/200314/3/2003
140 km/hr140 km/hr 80 km/hr80 km/hr
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Rollovers & SeatbeltsRollovers & Seatbelts
2 RTA’s:2 RTA’s:
what differences?what differences?
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Rollovers & SeatbeltsRollovers & Seatbelts
The difference is:The difference is:
SpeedSpeed(= kinetic energy)(= kinetic energy)
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Rollovers & SeatbeltsRollovers & Seatbelts
Rollovers happen when combining:Rollovers happen when combining:
- (high) - (high) speedspeed - sudden - sudden change of directionchange of direction - (- (brakingbraking when changing direction) when changing direction)
ALL caused by: ALL caused by: THE DRIVERTHE DRIVER! ! ..
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Rollovers & SeatbeltsRollovers & Seatbelts
The classic “S” curve rollover:The classic “S” curve rollover:
Mistake 2: pull hard leftMistake 2: pull hard left could roll here already could roll here already
Mistake 3: pull hard right Mistake 3: pull hard right
Mistake 1: lost concentration / tyre blowMistake 1: lost concentration / tyre blow car moves slowly car moves slowly to the right (or left) to the right (or left)
Driver suddenly realises this !!Driver suddenly realises this !!
Mistake 4: braking & turningMistake 4: braking & turning at the same time at the same time
Roll!! Roll!!
Roll? Roll?
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Rollovers & SeatbeltsRollovers & SeatbeltsA rollovers happens when combining:A rollovers happens when combining:
- (high) - (high) speedspeed - sudden - sudden change of directionchange of direction - - brakingbraking when changing direction when changing direction
ALL caused by: ALL caused by: THE DRIVERTHE DRIVER! ! ..
He does this because of:He does this because of:
• Lack of concentrationLack of concentration and “suddenly” and “suddenly” appearing other road usersappearing other road users
• Tiredness (falling asleep)Tiredness (falling asleep)
• Entering a dust cloudEntering a dust cloud
• Tyre blowout (not often)Tyre blowout (not often)
• Mechanical failure (not often)Mechanical failure (not often)
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Rollovers & SeatbeltsRollovers & SeatbeltsThe classic “S” curve rollover:The classic “S” curve rollover:
How to avoid it !!!How to avoid it !!!
Good re-action: Good re-action: Roll-out into the desert.Roll-out into the desert.Do NOT pull your steering Do NOT pull your steering wheel. Hold it tight and wheel. Hold it tight and straight with 2 hands.straight with 2 hands.Brake slowly to full STOP.Brake slowly to full STOP.Do NOT panic.Do NOT panic.
Mistake:Mistake:lost concentration / tyre blownlost concentration / tyre blown car moves slowly car moves slowly to the right (or left) to the right (or left)
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Rollovers & SeatbeltsRollovers & Seatbelts
4WD and Rollovers4WD and Rollovers
Are they better or worse Are they better or worse than 2WD ? than 2WD ?
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Rollovers & SeatbeltsRollovers & Seatbelts
4WD are great cars: 4WD are great cars:
• strong (we think)strong (we think)
• goes anywhere (almost)goes anywhere (almost)
• never get stucknever get stuck
• sit high (good view)sit high (good view)
• powerful & feel good (macho?)powerful & feel good (macho?)
• comfortablecomfortable
• carry big loads / many passengerscarry big loads / many passengers
BUT…….BUT…….
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Rollovers & SeatbeltsRollovers & Seatbelts
But 4WD:But 4WD:
• High CoG: sensitive to rolloversHigh CoG: sensitive to rollovers
• Heavy: poor brakingHeavy: poor braking
• Steering/cornering: not greatSteering/cornering: not great
• False sense of security: invulnerable at speedFalse sense of security: invulnerable at speed
• Powerful & fast: much too fast for handling abilityPowerful & fast: much too fast for handling ability
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Rollovers & SeatbeltsRollovers & Seatbelts
Would you drive these cars in the same manner when taking a corner or bend ? Would you drive these cars in the same manner when taking a corner or bend ? Of course NOT !Of course NOT !
4WD High CoG car: adjust your driving & speed.4WD High CoG car: adjust your driving & speed.
Low CoGLow CoG
CCentre entre oof f GGravityravity
High CoGHigh CoG
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Rollovers & SeatbeltsRollovers & Seatbelts
When driving (especially for 4WD):When driving (especially for 4WD):
• Adjust your driving style. Adjust your driving style.
– SpeedSpeed
– Steering: no sudden direction changesSteering: no sudden direction changes
– Braking: earlier, more distanceBraking: earlier, more distance
• Keep heavy loads low: NOT on the roof! Keep heavy loads low: NOT on the roof!
• Keep loads balanced: centre/middle.Keep loads balanced: centre/middle.
• Passengers are load: they change the stability of the car.Passengers are load: they change the stability of the car.
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Rollovers & SeatbeltsRollovers & SeatbeltsHow can you prevent Rollovers? Remember the Physics!How can you prevent Rollovers? Remember the Physics!
• SpeedSpeed Slow down !Slow down !
• Turn: not turningTurn: not turning
– Wrong reaction? Wrong reaction? Train yourself Train yourself NOT to oversteer – roll out NOT to oversteer – roll out
straightstraightand NOT to brake! and NOT to brake!
• Turn: not getting surprisedTurn: not getting surprised– Lack of concentration? Lack of concentration? Concentrate!Concentrate!– Tiredness? Tiredness? STOP, rest, have a nap!STOP, rest, have a nap!– Dust? Dust? Do NOT enter the dust cloud!Do NOT enter the dust cloud!– Other road users?Other road users? Drive defensivelyDrive defensively– Tyre blowouts? Tyre blowouts? Check condition, pressureCheck condition, pressure
• Lower COGLower COG Use a 2WD instead of a 4WDUse a 2WD instead of a 4WDLoad cars “low” and “centred”Load cars “low” and “centred”
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Rollovers & SeatbeltsRollovers & Seatbelts
I am in a rollover !I am in a rollover !
WHAT will protect me?WHAT will protect me?
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Rollovers & SeatbeltsRollovers & Seatbelts
I am in a rollover !I am in a rollover !
WHAT will protect me?WHAT will protect me?
• roll-bar roll-bar
• seat beltsseat belts
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Rollovers & SeatbeltsRollovers & Seatbelts
Seat belt in a rollover:Seat belt in a rollover:
Keeps you Keeps you
INSIDE INSIDE
the carthe car
Video 3Video 4
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Rollovers & SeatbeltsRollovers & SeatbeltsSeatbelt physicsSeatbelt physics
Kinetic Energy: ½ MKinetic Energy: ½ Mvv22 = F x d = F x d
This energy is dissipated by This energy is dissipated by braking (force F) over a distance (d)braking (force F) over a distance (d)
MM = = mass mass (kg)(kg)
vv = = speed speed
(m/s)(m/s)
F d
v v=0
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Rollovers & SeatbeltsRollovers & Seatbelts
Stopping Distance (m) Stopping Distance (m)1 0.5 0.1 1 0.5 0.1
Speed (km/hr) Stopping Force (kgf) Stopping Force (g)
40 300 600 3,100 6 12 62
60 695 1,390 6,950 14 28 139
80 1,240 2,500 12,400 25 49 247
100 1,900 3,900 19,300 39 77 386
120 2,800 5,600 27,800 56 111 556
Force on 50 kg body (kgf) G-Force on a body
Seatbelt physicsSeatbelt physics
Increase the stopping distance (d)Increase the stopping distance (d)Reduce the force on the body (F)Reduce the force on the body (F)
MM = = mass mass (kg)(kg)
vv = = speed speed
(m/s)(m/s)
V5
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Rollovers & SeatbeltsRollovers & Seatbelts
Video 6Video 7Video8
Seat belt:Seat belt:
The “The “UNBELTED”UNBELTED” person person
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Rollovers & SeatbeltsRollovers & Seatbelts