1. T-1430 Heavy vehicle rollover prevention program
This work has been produced by DGL (Aust) Pty Ltd
12/07/2006 Rev B

2. Before you get started 12/07/2006 Rev B
It is important that you complete all sections in this learning tool as it has been designed so that
You can abide by the procedures of our organization.
You can apply what you have learnt in this package in your day to day activities
This Learning Tool is designed to be relevant only to DGL (Aust) Pty Ltd employees and only applied whilst employed with DGL (Aust) Pty Ltd
You may have already acquired knowledge in the area identified in this package as you may have completed some specialized training. Or you may have been working within the industry for some time. Should you identify any improvement opportunities in the information contained in this package or have difficulties completing the package please contact
National Training and Compliance Manager
DGL (Aust) Pty Ltd
PO BOX 1594
EAGLE FARM QLD 4009 Ph
Fax
12/07/2006 Rev B

3. Create awareness to all stakeholders Preserve driver
Aims to -
Create awareness to all stakeholders
Preserve driver
Reduce resultant trauma
Improve productivity
Reduce impact on environment
Reduce impact on community
Truck washer to bean counters, road designers, road builders, community,
Drivers cost money to replace, they are far too valuable to not look after. Use integrated seat belts, no loose cabin material, etc
$70,000 before even fixing the truck or driver
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4. Factors that influence roll-overs
There is a lot of factors, this training package focuses on the items listed below in red
Gravity
Speed
Changing direction
Acceleration.
Driver experience.
Sloshing.
Load movement.
Type of load.
Restraints
Friction
Centre of Gravity
Driver alertness
Sun
Wind
Brake condition
Couplings
Number of trailers
Camber change in turn
Road litter
Engine failure
Missed gear
Inappropriate selection
Lane change downhill
Suspension
Tyre condition
Tyre pressure
New tyres
Axle alignment
Suspension type
Time pressure
Other road users
Mobile phones
Road knowledge
Centrifugal Force
Roundabout size
Round-A-Bout Camber
Lack of time intersection
Intersection size
Tight Corners
Wrong Camber
Road condition
On ramps
Off ramps
Load location
Load viscosity
Load packing
Low tare weights
Gross weight
Load heights
Bed heights
Trailer format
There is a lot of factors but we will only be able to consider these in the time we have
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5. Roll Over facts
More than half truck driver deaths are due to rollovers.
Most rollovers are entirely preventable.
Advisory speed signs on highways are meant for cars, and are not safe for high center of gravity vehicles such as tankers.
Rollovers are mostly caused by one thing:
EXCESSIVE SPEED
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6. Primary Causes of rollovers
1. Entering a curve at too high a speed
2. Swerved to avoid an obstacle
3. Fatigue, fell asleep, drove off the road
4. Stopping or parking on a soft surface
5. Truck improperly loaded
6. Sudden maneuvers due inattention to the road.
7. Driver distracted, drifted off the road
MOST OF THESE CAUSES ARE AVOIDABLE
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7. Video of load restraint test
The following video shows a vehicle test for load restraints,
The vehicle is travelling at 56 klm an hour
It is not a test for a roll over.
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8. Load restraint test video
This is a test of load restraints, not a test for a roll over. Lets watch the first run.
Now, when did the driver know he was in trouble?
[step to 90]
did he know before this? Then why aren’t his brake lights on?
He did not know until the trailer had dropped 90 degrees.
Now see how the cabin is flipped rapidly. The trailer has wound up like a spring and then released.
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9. 12/07/2006 Rev B

10. 12/07/2006 Rev B

11. 20 T The forces to loads 12/07/2006 Rev B centrifugal
Centre of gravity
suspension
[Do the model of the tilt tray.]
Truck rollover demo, where does it roll? 50-60
Trailer with logs, before tip ask the question “so, where do you think it will roll?”
[Tip, emphasise the smallness of 15 degrees and this is still static!]
friction
gravity
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12. The physics of roll overs
Rollovers can be categorized into two types:
Tripped,where the vehicle leaves the roadway and slides sideways digging it’s tires into soft soil, or where it hits an object such as a guardrail or curb. The high tripping force causes a rollover.
Untripped,where the vehicle does not hit an object, but rolls over due to centrifugal force, usually during high speed turns or sudden steering maneuvers. Tankers with a high center of gravity are more prone than passenger cars to untripped rollovers.
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13. Speed and Centrifugal force
If a vehicle is forced to take evasive action, these
forces are further multiplied.
                                                                        
What to do:
Now we add the first dynamic force to the problem. Centrifugal force is due to two basic forces, speed and rate of change in direction. The tighter the turn the greater the force, the higher the speed the greater the force. BUT it does not just increase in a linear fashion, like 10% increase in speed causes 10% increase in force.
It increases by squaring so that 10% increase in speed causes 100% increase in force! Double the speed is four times the force!
Rearward amplification is a typical problem when you need to counter steer or swerve around a problem. That is a whipping effect when a small change in steering is amplified by the trailer.
If you double your speed, the overturning force will be four times higher.
As the speed increases the trailer tracks wider and forces increase on rear axle. This means that a slight increase in speed can be critical.
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14. The effect of road camber
Road camber is the slope built into road surfaces to assist water run-off and to reduce rollover tendency on turns.
When traveling straight, road camber will result in the gravitational forces moving outwards, increasing the chances of a rollover, (red arrow).On a properly cambered turn, at the design speed, the centrifugal forces will result in the gravitational effect returning to normal, (green arrow).
However at speeds above or below the road design speed, the forces will not be in balance and there will be a tendency to roll into the turn (below design speed) or out of the turn (above design speed).
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15. The effect of poor maintenance
Poor truck maintenance can reduce handling ability and reduce the speed at which a rollover can occur.
Under or over inflated tires reduce truck handling ability, especially in turns.
Incorrect brake adjustment and improper balance between prime mover and trailer brakes can increase the chance of a rollover.
Poorly adjusted and worn suspension components, broken spring leaves reduce handling ability
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16. Video of centrifugal forces
The following slide contains a video demonstrating centrifugal force acting on a truck as it turns. Both speed and change in direction create this force, but you can clearly see, that it is only a marginal increase in speed and angle compared to the truck that negotiates the bend safely.
Run the video twice, and try to pick out where the truck corrected the second time which was a 30cm movement, look at the white line width for a guide
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17. Video of centrifugal forces
This is a demonstration of centrifugal force acting on a truck as it turns. Both speed and change in direction create this force, but you can clearly see, that it is only a marginal increase in speed and angle compared to the truck that negotiates safely.
[run the video twice, second time point out the minor correction point which followed the pick up, then, show where the truck corrected the second time which was a 30cm movement, look at the white line width for a guide]
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18. Vehicle roll over on a corner
The following slide has a video and is an example of centrifugal force at speed, not speeding.
The driver is travelling the same speed as the other cars, The drivers is just going to fast for his load and road conditions ‘inappropriate speed’ .
It is clear that the rear trailer bogie is off the ground even before you can see it. By the time he is in the centre of the picture, the truck is beyond saving and a crash is inevitable.
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19. Video of roll over 12/07/2006 Rev B
This is an example of centrifugal force at speed, not speeding, he is not going faster than the cars, just going to fast for his load and road conditions. The term is ‘inappropriate speed’ . It is clear that the rear trailer bogie is off the ground even before you can see it. By the time he is in the centre of the picture, the truck is beyond saving and a crash is inevitable.
The load appears to be a large number of small boxes, and is loaded very high. Recall the centre of gravity issue.
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20. A vehicle can roll travelling in a straight line
Now that you have all the dynamics forces in mind, and you think you have it under control, along comes the environment. The following slide has a movie of a light load going over.
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21. Video of Roll over 12/07/2006 Rev B
Now that you have all the dynamics forces in mind, and you think you have it under control, along comes the environment. The load you carry is affected by the environment, here we have a light load going over.
Any ideas on what he could have or should have done?
Check the weather, know your load, go a different way, if you cant, then go tomorrow! This is not a bad one, but it could be a fatal if it fell on a car beside it.
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22. All this leads to the ‘1k’ factor
Summary of the forces
We have fixed forces such as gravity and friction, which will always be there.
There are dynamic forces such as centrifugal force, which is dependant on rate of change of direction and speed, and add Centre of Gravity
Then the dynamic c forces which are affected by the dynamic forces above but react differently and independently
Summary of the forces
We have fixed forces such as gravity and friction, which will always be there.
There are dynamic forces such as centrifugal force, which is dependant on rate of change of direction and speed, and add COG
Then the dynamic dynamic forces which are affected by the dynamic forces above but react differently and independently, such as milk slosh, or one sided concrete rise with agitator rotation force.
When …..
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23. Forces….summary Unknowns … environment, other road users,
Fixed, constant types - gravity
Dynamic truck forces – centrifugal, speed, COG
Dynamic load forces, compounding on the truck
Unknowns … environment, other road users,
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24. Case study
The following slides contain information of an actual study into an event of a roll over
The vehicle involved in this event is not a DGL vehicle
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25. Load restraint issue, caused a rollover
Why
Driver had not carted this load before
High COG load (2 more packs than normal)
Load restraint and movement
Suspension tilt
New tyres
Truck had minor change of direction
Fatigue
Negotiated corner at approximately 85kmh as usual
Corner had developed bumps just prior to apex
Demo load restraint with wood pack.
Driver was experienced but had not carried this load before.
The load had a higher COG than he was used to.
The load although well restrained to meet the load restraint guide but was able to move at the top due to the 90deg strap angle.
Suspension tilt was magnified due to this change in COG.
Drivers had reported that the new drive tyres that were being used made to truck prone to wandering for the 1st 500km.
The truck had a minor change of direction to the left, (maybe due to deep tread new tyres, load movement or fatigue, the driver had to counter steer.
He negotiated the corner as usual, but the 85kmh corner characteristics had changed since the bumps appeared.
When we add all of these minor issues together, we had a roll-over…Take any away and it may not have occurred.
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26. Corrective actions from incident
Induction and mentoring program for drivers
All company personnel have attended a rollover awareness course
Drivers retrained on load restraint and re-tensioning of straps
Loading and restraint methods are being reviewed by all parties in the transport chain
The operator immediately set about putting actions in place to address the issues that were found,
Some of these were-
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27. What can you do? Be aware of the limits, not just your job
Back off more from the limits, not just speed
Educate others, this is not a driver problem alone
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28. Key points As little as 1 kph extra will make you roll over
If you are aware, and you add more than the 1kph space, that is give yourself decent headroom to allow for unknowns, you will get home without a roll over
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29. Even with the best technology
A trailer design with low center of gravity and good rollover stability will help in raising the critical speed when a rollover may occur.
Electronic Stability control will help in avoiding a rollover in high speed situations.
But…… it all comes down to the driver
Drive at speeds which are safe for the situation,
Don’t rely on the technology to protect you.
Slow down, stay alert, remain in control.
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30. The Primary Causes of Rollovers
Let’s analyze how we can prevent a rollover in each of
these seven situations:
Entering a curve at too high a speed
Swerved to avoid an obstacle
Fatigue, feel asleep, drove off the road
Stopping or parking on a soft surface
Truck improperly loaded
Sudden maneuvers due inattention to the road.
Driver distracted, drifted off the road
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31. Entering a turn at too high a speed
Slow down on turns and curves, at least 10 KPH below the posted advisory speed.
Always use the speedometer to know your speed. Check your speed before you come to the curve.
Do not judge your speed by what it feels like, you will probably be wrong.
After driving for a long time at highway speeds, you become used to the speed and you generally under-estimate your actual speed. It may “feel” like you are doing 80 KPH, but in fact you are probably going KPH faster.
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32. Swerving to avoid obstacles
Making sudden maneuvers at speed with a high center
of gravity truck is asking for a rollover.
It may be instinctive to turn sharply to miss an obstacle,
especially if it’s a person, so don’t put yourself into a
position where this is necessary.
Always leave yourself plenty of clear vision ahead.
Maintain plenty of following distance (at least four seconds)
Plan an escape route if you can’t foresee a clear safe exit, slow down
and increase your following distance.
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33. Fatigue, Fell asleep, Drove off the road
As a professional driver, you have been taught the
angers of fatigue, and you are expected to report for
duty in a fit condition to drive, so:
Get sufficient rest before you commence driving.
Observe the fatigue laws.
Take your on-road rest breaks
And if you feel drowsy, STOP, for your own safety and the safety of the other road users.
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34. Stopping or parking on soft surfaces
Road side verges are not usually meant to carry the load of a heavy truck. If one axle group subsides into a soft surface, gravity takes over, and the truck will end up on it’s side.
Plan where you pull off the road to stop. Look for
paved or other hard surfaces.
Avoid unmade surfaces.
Choose a flat area.
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35. Don’t park near ditches and excavations
Leave plenty of space between the offside of your truck and a ditch or a roadside excavation.
AVOID:
Soft shoulders
Sloping surfaces
Water-logged surfaces
Embankments
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36. Truck improperly loaded
Incorrect load restraint can result in load shift and during a turn and this increases the centrifugal force, and can cause a rollover, even at speeds as low as 15 KPH.
An unbalanced load, especially with full rear compartments and empty front ones, will result in reduction in steering, and can cause “fish-tailing”and loss of control resulting in a rollover.
Leave with a balanced load, and if doing multiple drops, plan the drops so that the truck axle loadings remain balanced.
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37. Sudden Maneuvers due to Inattention to the Road
Sudden sharp turns at too high a speed are sure to cause a rollover.
Driving is a full time job, keep your attention on the road and the area ahead.
•Never let yourself get into a situation where because of inattention, you have to make a sudden steering adjustment.
•If you do leave the paved surface, don’t swing back sharply. Reduce speed, and when slowed turn gradually
back onto the road.
•Always maintain the big picture, then there won’t be any surprises, and you’ll have time to brake or make a
smooth turn if you have to avoid an object.
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38. Driver distracted, drifted off the road.
Don’t be distracted by things that happen or things you see either
inside or outside the cab.
At 100 KPH, your truck travels around 26 metres in one second. That’s more than enough time for your truck to drift off the road onto the verge, and it can be very difficult to recover, especially if the ground is soft, or sloping.
Ensure all objects carried in the cab are secured.
Ignore external objects that are irrelevant to your driving, such as advertising signs, nice views and the general surroundings.
Never let yourself get into a situation where because of inattention, you have to make a sudden steering adjustment.
Always maintain the big picture, then there won’t be any surprises, and you’ll have time to brake or make a smooth turn if you have to avoid an object
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39. Test your knowledge
Through the following slides you will be asked an number of questions to show that you have understood the content of this learning tool
Please record your answer on the training form F-260.
You will be required to submit the answers to the DGL HSEQ unit
7/29/2018

40. Question 1 In one second a vehicle travelling at 100 kph will travel
a) 26 Metres
b) 16 metres
c) 6 metres
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41. Question 2
When entering a curve an operator should slow down at least,
a) at least 10 KPH below the posted advisory speed
b) at least 5 KPH below the posted advisory speed
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42. Question 3
As the centre of gravity increases then so does the risk of vehicle roll over
a) True
b) False
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43. Question 4
Road camber allows trucks to travel the same speed as cars when going around corners
a) True
b) False
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44. Question 5
Inappropriate speed is a contributing factor in vehicle roll overs
a) True
b) False
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45. Additional information
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