Bigger is not always better, sometimes it’s deadlier

The Tiger Woods car crash this week – when the 45 year old golfer suffered serious leg injuries when his Genesis GV80 (Hyundai’s upmarket brand) SUV rolled over and crashed in California – is yet another warning about the inherent dangers many of these vehicles pose – even the most up-to-date models.

The harsh truth – which many manufacturers coyly avoid and salespeople will never mention to you in the  showroom – is these vehicles are at a higher risk of a rollover than an ordinary sedan or hatchback car. And that’s because of a simple principle of physics, their centre of gravity.

Scientifically, this is defined as the point at which the weight of an object is evenly dispersed and all sides are in balance. In the case of most SUVs, this is higher than in sedans and hatchbacks, because the SUV stands taller, mainly thanks to its raised ground clearance.

A tall object like an SUV, van or truck is likely to be more easily disturbed by the sudden application of additional forces than is a normal vehicle. That has been known for years and until about 40 years ago, that wasn’t much of a problem, because SUVs particularly couldn’t really go fast enough to get themselves into trouble.

However, the global market for SUVs has mushroomed and many of them have become fast vehicles in their own right.

The SUV Tiger Woods was driving is capable of a top speed of more than 200km/h and acceleration on par with a decent sports car of 20 years ago.

The problem is when power and speed meet a sudden emergency manoeuvre – avoiding a pedestrian or animal, or a pothole, for example – then the already high centre of gravity of an SUV can be disturbed to the extent
that the tyres can no longer support the weight. The vehicle then either falls on it is side or, if the velocity is high enough, rolls over.

That is why, in the “old days” drivers of tall off-road vehicles never travelled too fast, even in the unlikely event they had the power to do so.

Today, many SUVs (as well as double cab bakkies) have the power and speed to travel fast. But generally, because of their size and centre of gravity limitations, as well as compromise on off-road tyres, their braking performance is not as good as equivalent sedans.

Some manufacturers warn owners about the dangers of a rollover. Toyota, along with Land Rover, as well as Asian carmakers, do – but how many drivers bother to read the handbook?

Graphics: Costa Makola

It is true that a bigger vehicle comes off better against a small one in a collision but the myth about SUVs being safe is just that…

In the US, 70% of all rollover accidents involve SUVs, despite the vast improvements in safety systems across all vehicle categories in the past decade. And when occupants don’t wear their seatbelts (Woods was wearing his), the results are often tragic.

Graphics: Costa Mokola

There are two examples close to home about how dangerous an SUV can be.

In April 2006, R&B star Ashanti Douglas had to pull out of a concert in Johannesburg when her cousin was killed in a car crash in Randburg. Quinshae Snead, 20, was flung from a BMW X5 SUV when it rolled after being rear-ended by a speeding Toyota Corolla. She was thrown into the oncoming lane and hit by another vehicle.

Graphics: Costa Mokola

Had the BMW been a 5 Series sedan, the Corolla would merely have smashed into it, instead of going underneath and flipping it over.

In October 2006, local singing sensation Lebo Mathosa died when her driver lost control of her Toyota Prado SUV on the N3. The Prado was the short-wheel-base model, which would be even more vulnerable to a rollover in high speed avoidance manoeuvres.

Moral of the story: buy an SUV if you must, but be aware of its shortcomings. Get some training about driving in emergency situations, too.

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