The Vehicular Obesity Epidemic: Cars & SUVs are getting overweight

You can’t open a newspaper or a magazine these days without staring at a headline about the obesity epidemic. But it’s not just waistlines that are rapidly expanding – vehicles are, too.

It’s a worry because, as good as those vehicles are, the basic physics can’t be overlooked – hauling around more mass means consuming more fuel. And burning more fuel means emitting more CO2, if you care about that sort of thing. As a nation, we probably can’t afford to burn more than the 30 billion-odd litres that are currently going up in smoke annually.

Stuffed if I know about the environment. I’m no expert on that, and there seems to be robust dispute between opposing ‘expert’ camps. But the one thing I do know is, Australia has dwindling reserves of crude oil. And that means, economically, we’ll be increasingly dependent on foreign oil supplies – most of which comes from potentially unstable regimes that fundamentally hate the west.

I mean, it really would be better if the Middle East supplied two-thirds of the earth’s known reserves of broccoli instead of oil … but things seldom work out exactly as you’d hoped.

The other factor is China and India – both are emerging superconsumers of resources. China alone has the capacity to double the number of cars on earth, when they enjoy the same per-capita vehicle ownership as the west. And India can almost match China. So if you think global demand for oil is set to fall, you’re living in a fool’s paradise.

This means in coming decades – maybe two decades – our capacity to travel might be severely compromised. It’ll probably happen like this: big jump in global demand for oil pushes prices sky-high. There could be a global shortfall in oil production versus demand. Petrol could be $10 per litre or more in that timeframe. And it might be rationed if, as a nation, we can’t buy enough. That’ll put a dent in those upcoming ‘big trip’ plans.

Much of the car industry’s messaging about cutting consumption and increasing efficiency is spin. Yes, big advances have been made in efficiency. And yes, construction advances using high-strength-to-weight materials have been achieved.

And what has the car industry done with these advances? Generally, they’ve made engines more powerful and put them in bigger vehicles, with higher equipment levels.

To illustrate this point, take Toyota’s LandCruiser. Fifteen years ago, in 1995, an 80-Series petrol GXL auto weighed 2163kg. Its 4.5-litre straight six delivered 158kW. It had a payload capacity of 797kg.

Fast-forward to 2000: the 100-series GXL upped the ante in every sense. Weight climbed 12 per cent to 2413kg. Engine power jumped just four per cent to 165kW … which, interestingly isn’t enough to offset the vehicle’s increased mass, compared with the 80. Payload capacity actually fell 30kg (probably due to tyres). In a nutshell, bigger and heavier – despite an efficiency advance that allowed the Big T to dial up an additional 7kg out of essentially the same engine.

Next, the 200: Compared with the 80-series, it’s 22 per cent heavier, at 2635kg. Engine capacity has increased 0.2 litres (it’s also a V8), and power is up 28 per cent – so at least this model out-performs its 80-Series equivalent notionally by about six per cent. And it’s full of fruit, in comparison … which maybe explains why payload capacity has jumped into the express elevator and hammered the ‘basement’ button. The 80 GXL allowed 797kg of payload, while the 200 can hold just 665kg – a reduction in carrying capacity of 17 per cent.

First point to note is that a lot of impressive engine development work allows Toyota to deliver 28 per cent more power from an engine with just four per cent more capacity – it could translate to a real fuel consumption improvement if the 200 weren’t also saddled with lugging around the automotive equivalent of the beer gut from hell.

And it’s not just Toyota; everyone’s doing it. The current 2.4-litre Mitsubishi Lancer weighs the same as, and is the same size as, and makes the same power output as, the very first VB Commodore with single-exhaust 5.0-litre V8 engine. It makes you think.

Tremendous strides in efficiency and construction technology mean small cars are now big (it’s one of the reasons why Toyota had to invent the Yaris – the Corolla was no longer a small car). It means big cars are now huge, and 4X4s are expanding in concert.

The car industry will tell you it’s just building cars in response to consumer demand. And that’s true. Everyone wants a slightly bigger version of the vehicle they have now – preferably with more power, more fruit and better safety features.

Unfortunately, this ‘more is more’ mentality could well be unsustainable. The growth of vehicles – 4X4s and cars – over the past 20 years is likely to fall flat on its face when we hit the next major oil shock. It almost did for GM when oil last went through the roof in 2008.