Overturned vehicles involve mostly trucks with heavy loads
The following article was published by Channel NewsAsia on 25 Feb 2008.
Overturned vehicles involve mostly trucks with heavy loads
25 February 2008
Channel NewsAsia
SINGAPORE : The MediaCorp News hotline received eight calls about accidents involving overturned vehicles, between December last year and the first week of February this year.
This compares to just two cases between October and November last year.
And these are just the numbers in our records.
Traffic Police say there are no exact figures of overturned vehicles in the past few months.
This is because only accidents with injuries or fatalities are recorded.
From the reports we received, most involved trucks carrying heavy loads.
Experts say longer vehicles like trailers and lorries carrying such loads are most at risk of overturning.
The reason is these vehicles have a higher centre of gravity.
So a normal car with just front or back two-wheel drive has a lower risk due to its lower centre of gravity. On August 23 last year, a tragic accident happened.
A foreign worker was killed when he and 13 others were flung out of a lorry, along the Pan Island Expressway after their vehicle overturned.
And when vehicles topple, it usually involves trucks and lorries carrying heavy loads.
Associate Professor Seah Kah Heng, Department of Mechanical Engineering at the National University of Singapore, said: "The centre of gravity might be quite high because they pack the cargo, and they try to pack as much as possible. Sometimes you pack the cargo to such an extent that you are not aware that the centre of gravity has gone up so much. And it is extremely dangerous to go around the corner fast."
"When you go round a sharp corner, there's such a thing called the centrifugal force. It is a force that tends to overturn the car out of the corner.
"If you are talking about trailers, some trailers have got this hinge between the prime mover and whatever cargo you're pulling. When it turns a corner, there will be some lateral or side force pulling it sideways. So that force can also cause a vehicle to overturn."
The centrifugal force is calculated based on the mass, the velocity of the vehicle and the radius of the curve.
The sharper the turn, the greater the force will act on a vehicle if a motorist is coming down at high speed.
Based on the formula, if a motorist is driving twice as fast, he will create four times a greater centrifugal force which means he is four times more likely to have his vehicle overturn.
And braking hard while driving straight can also tip a car over.
Professor Seah said: "Sometimes the brakes right and left, front and back are not balanced, and that gives the car a certain fall sideways as well. When you brake the tyre, if the tyres are not worn out evenly, it can pull the car to one side. And that can cause overturning. If something is on the road, like causing a bump, or the road is not even. That's another possibility causing the car to overturn."
The Automobile Association of Singapore says it is crucial for motorists to check their tyres regularly.
If they are not inflated properly or they are already worn out, a motorist may lose control of your vehicle. - CNA/de
(c) 2008 MediaCorp News Pte Ltd. All Rights Reserved
Overturned vehicles involve mostly trucks with heavy loads
25 February 2008
Channel NewsAsia
SINGAPORE : The MediaCorp News hotline received eight calls about accidents involving overturned vehicles, between December last year and the first week of February this year.
This compares to just two cases between October and November last year.
And these are just the numbers in our records.
Traffic Police say there are no exact figures of overturned vehicles in the past few months.
This is because only accidents with injuries or fatalities are recorded.
From the reports we received, most involved trucks carrying heavy loads.
Experts say longer vehicles like trailers and lorries carrying such loads are most at risk of overturning.
The reason is these vehicles have a higher centre of gravity.
So a normal car with just front or back two-wheel drive has a lower risk due to its lower centre of gravity. On August 23 last year, a tragic accident happened.
A foreign worker was killed when he and 13 others were flung out of a lorry, along the Pan Island Expressway after their vehicle overturned.
And when vehicles topple, it usually involves trucks and lorries carrying heavy loads.
Associate Professor Seah Kah Heng, Department of Mechanical Engineering at the National University of Singapore, said: "The centre of gravity might be quite high because they pack the cargo, and they try to pack as much as possible. Sometimes you pack the cargo to such an extent that you are not aware that the centre of gravity has gone up so much. And it is extremely dangerous to go around the corner fast."
"When you go round a sharp corner, there's such a thing called the centrifugal force. It is a force that tends to overturn the car out of the corner.
"If you are talking about trailers, some trailers have got this hinge between the prime mover and whatever cargo you're pulling. When it turns a corner, there will be some lateral or side force pulling it sideways. So that force can also cause a vehicle to overturn."
The centrifugal force is calculated based on the mass, the velocity of the vehicle and the radius of the curve.
The sharper the turn, the greater the force will act on a vehicle if a motorist is coming down at high speed.
Based on the formula, if a motorist is driving twice as fast, he will create four times a greater centrifugal force which means he is four times more likely to have his vehicle overturn.
And braking hard while driving straight can also tip a car over.
Professor Seah said: "Sometimes the brakes right and left, front and back are not balanced, and that gives the car a certain fall sideways as well. When you brake the tyre, if the tyres are not worn out evenly, it can pull the car to one side. And that can cause overturning. If something is on the road, like causing a bump, or the road is not even. That's another possibility causing the car to overturn."
The Automobile Association of Singapore says it is crucial for motorists to check their tyres regularly.
If they are not inflated properly or they are already worn out, a motorist may lose control of your vehicle. - CNA/de
(c) 2008 MediaCorp News Pte Ltd. All Rights Reserved
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