Rollovers & Seatbelts 0 Rollovers & Seatbelts

Rollovers & Seatbelts 1 What is a “ROLLOVER”?

Rollovers & Seatbelts 2 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”

Rollovers & Seatbelts 3 Does PDO have many “ROLLOVERS”?

Rollovers & Seatbelts 4 PDO: many rollovers every year! PDO: many rollovers every year! td Rollovers Km Rollovers

Rollovers & Seatbelts 5 19-Oct-2007: on the way to Bahja Driver: seatbelt – minor injury Passenger: Seatbelt – minor injury Passenger: NO seatbelt - DEAD Rollover !!

Rollovers & Seatbelts 6 9-Sept-2007: on the way to Haima Driver: NO seatbelt - DEAD Passenger: NO seatbelt - DEAD Passenger: Seatbelt – minor injury Rollover !!

Rollovers & Seatbelts 7 2-Aug-2007: Qarn Alam Driver died – no seatbelt – head crushed under vehicle Rollover !!

Rollovers & Seatbelts 8 23-Oct-2006 Marmul-Thumrait 7 km before Harweel junction Driver: 39 yrs old, died Speed: at least 140 km/hr PDO Spec vehicle: tampered! Seatbelt did not help anymore Rollover !!

Rollovers & Seatbelts 9 March/2001 Maqbool & Faisal Died Anything that goes wrong at high SPEED is a BIG problem!! 150 km/hr Tyre blew Rollover !!

Rollovers & Seatbelts 10 30/Oct/01 LTI Permanent Total Disability Veered off to the right Overcorrected, rolled 4x Classic S pattern NO rollover bar Straight blacktop Fahud-Nahada Rollover !!

Rollovers & Seatbelts 11 Rollover !! Blacktop road Fahud- Nizwa Car moved right at high speed. Driver over corrected and got into an S pattern: Rolled & Flipped. 20/Nov/01 Fatality & LTI

Rollovers & Seatbelts 12 2 man came out alive. They were wearing their seatbelts. 1 man DIED. He was NOT wearing his seatbelt NO Seatbelt = DEATH Nimr to Muscat 13th June 98

Rollovers & Seatbelts 13 What would you “prefer”? a Rollover or a Head on Collision

Rollovers & Seatbelts 14 Rollovers are killers! Rollovers are killers! No of accidents No of death Video 1 Video 2

Rollovers & Seatbelts 15 Common features of rollovers: Speed (80 km/hr can be too fast !!)Speed (80 km/hr can be too fast !!) Mostly 4 WD (high Centre of Gravity cars)Mostly 4 WD (high Centre of Gravity cars) Most on straight roadsMost on straight roads Most classic “S” curvesMost 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

Rollovers & Seatbelts 16 Why does a vehicle roll ? How many rolls will it do ? Simply Physics ! Understand the physics to understand the controls……

Rollovers & Seatbelts 17 We have a “vehicle at speed”: why does it roll? Gravity Force GF = M x g (= constant) M= mass (kg) v= speed (m/s) g= gravitational acceleration Centre of Gravity

Rollovers & Seatbelts 18 Why does it roll?.... Because of centrifugal force! Gravity Force GF = M x g (= constant) Centrifugal Force (CF) M= mass (kg) v= speed (m/s) r = turn radius (m) g= gravitational acceleration Centre of Gravity Mv 2 CF= r Mv 2 CF= r

Rollovers & Seatbelts 19 Why does it roll?.... Because of centrifugal force! Gravity Force GF = M x g (= constant) Centrifugal Force (CF) M= mass (kg) v= speed (m/s) r = turn radius (m) g= gravitational acceleration CF increases with: - v higher (higher speed) - r smaller (sharper turn) Centre of Gravity Mv 2 CF= r Mv 2 CF= r

Rollovers & Seatbelts 20 We have a “rolling vehicle at speed” How many rolls will it do ?

Rollovers & Seatbelts 21 We have a “rolling vehicle at speed” How many rolls will it do ? Kinetic Energy: ½ Mv 2 This energy is dissipated during the rolls More energy more rolls! Energy goes up with the square of the speed! M= mass (kg) v= speed (m/s) Km/hrEnergy in % of 100 km/hr 8064% % % %

Rollovers & Seatbelts 22 Next 4 slides: -2 RTA’s are shown -they are almost the same -compare them -see what the differences are -discuss why the outcome was different

Rollovers & Seatbelts 23 2 Black Top Roads 2 Cars driving 140 km/hr 80 km/hr 25/2/200314/3/2003

Rollovers & Seatbelts 24 2 Tires blown 140 km/hr 80 km/hr 25/2/200314/3/2003

Rollovers & Seatbelts 25 2 Rollovers 140 km/hr 80 km/hr 25/2/200314/3/2003

Rollovers & Seatbelts 26 Passenger 25 years old (driver’s son) Very badly Injured Will he ever recover? Driver: Dead 1 Dead 1 Badly Hurt Driver: Minor scratches and bruises No Injury 25/2/ /3/ km/hr 80 km/hr

Rollovers & Seatbelts 27 2 RTA’s: what differences?

Rollovers & Seatbelts 28 The difference is: Speed (= kinetic energy)

Rollovers & Seatbelts 29 Rollovers happen when combining: - (high) speed - sudden change of direction - (braking when changing direction) ALL caused by: THE DRIVER !.

Rollovers & Seatbelts 30 The classic “S” curve rollover: Mistake 2: pull hard left could roll here already Mistake 3: pull hard right Mistake 1: lost concentration / tyre blow car moves slowly to the right (or left) Driver suddenly realises this !! Mistake 4: braking & turning at the same time Roll!! Roll?

Rollovers & Seatbelts 31 A rollovers happens when combining: - (high) speed - sudden change of direction - braking when changing direction ALL caused by: THE DRIVER!. He does this because of: Lack of concentration and “suddenly” appearing other road usersLack of concentration and “suddenly” appearing 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)

Rollovers & Seatbelts 32 The classic “S” curve rollover: How to avoid it !!! Good re-action: Roll-out into the desert. Do NOT pull your steering wheel. Hold it tight and straight with 2 hands. Brake slowly to full STOP. Do NOT panic. Mistake: lost concentration / tyre blown car moves slowly to the right (or left)

Rollovers & Seatbelts 33 4WD and Rollovers Are they better or worse than 2WD ?

Rollovers & Seatbelts 34 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 passengersBUT…….

Rollovers & Seatbelts 35 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

Rollovers & Seatbelts 36 Would you drive these cars in the same manner when taking a corner or bend ? Of course NOT ! 4WD High CoG car: adjust your driving & speed. Low CoG Centre of Gravity High CoG

Rollovers & Seatbelts 37 When driving (especially for 4WD): Adjust your driving style.Adjust your driving style. –Speed –Steering: no sudden direction changes –Braking: 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.

Rollovers & Seatbelts 38 How can you prevent Rollovers? Remember the Physics! Speed Slow down !Speed Slow down ! Turn: not turningTurn: not turning –Wrong reaction? Train yourself NOT to oversteer – roll out straight and NOT to brake! Turn: not getting surprisedTurn: not getting surprised –Lack of concentration? Concentrate! –Tiredness? STOP, rest, have a nap! –Dust? Do NOT enter the dust cloud! –Other road users?Drive defensively –Tyre blowouts? Check condition, pressure Lower COGUse a 2WD instead of a 4WD Load cars “low” and “centred”Lower COGUse a 2WD instead of a 4WD Load cars “low” and “centred”

Rollovers & Seatbelts 39 I am in a rollover ! WHAT will protect me?

Rollovers & Seatbelts 40 I am in a rollover ! WHAT will protect me? roll-barroll-bar seat beltsseat belts

Rollovers & Seatbelts 41 Seat belt in a rollover: Keeps you INSIDE the car Video 3 Video 4

Rollovers & Seatbelts 42 Seatbelt physics Kinetic Energy: ½ Mv 2 = F x d This energy is dissipated by braking (force F) over a distance (d) M= mass (kg) v= speed (m/s) F d v v=0

Rollovers & Seatbelts 43 Stopping Distance (m) Speed (km/hr)Stopping Force (kgf)Stopping Force (g) , ,3906, ,2402,50012, ,9003,90019, ,8005,60027, Force on 50 kg body (kgf)G-Force on a body Seatbelt physics Increase the stopping distance (d) Reduce the force on the body (F) M= mass (kg) v= speed (m/s) V5

Rollovers & Seatbelts 44 Video 6 Video 7 Video8 Seat belt: The “UNBELTED” person

Rollovers & Seatbelts 45