The international standard...

The international standard kilogram is losing weight, according to

Mercs are now cheaper than in 1960. Perhaps Janis Joplin needed to be patient when asking for her Mercedes Benz

its French curators (who on Earth left the French in charge of something so important for Pete’s sake?). Apparently, last summer, after they’d finished playing football with it or something, they unwrapped it and put it on the bathroom scales, and (sacre bleu!) the platinum-iridium alloy cylinder didn’t weigh a kilogram any more.

We used to say that Italian cars often had smaller horses under their bonnets, but this raises the interesting possibility that French models could be measured in little tiny kilograms, and outside France they will therefore weigh a bit more than their makers claim.

It also got me thinking about how we measure our vehicles. Isn’t it time we had some new and simpler international standards that more of us would understand? What about the value of your car? You know the price of course, but if you include inflation, is a new model going to be cheaper or more expensive than your last one?

Does your head hurt? Fear not, for salvation comes in the form of a humble Mars Bar. It’s long been used by economists as a simple method of tracking values against inflation, and you can do the same with cars. So, in 1940, your grandad’s Morris 8 cost the equivalent of 19,200 Mars Bars. In 1960, your dad’s Mini cost the equivalent of 21,200 Mars Bars, while a 2004 Nissan Micra cost the equivalent of 23,857 Mars Bars. In other words, these small cars are getting more expensive, (at least in terms of Mars Bars), but not by much. Try the same calculation on more expensive motors and you get the opposite result.

In 1960, the Mercedes 220SE cost чЈ2,690 including tax, or 107,600 Mars Bars. Today’s equivalent might be an E-Class 200 Sport at чЈ31,372, or 69,715 Mars Bars. So, Mercs are cheaper, even if their servicing isn’t. Perhaps Janis Joplin only needed to be more patient when she sang ‘Lord, Won’t You Buy Me A Mercedes-Benz?’.

How about the measure of CO2 emissions, grams per kilometre? Do you know exactly what it means? I was munching through a packet of crisps the other day when I noticed that Walkers has started to print the entire carbon contribution of producing the crisps on the back of the packet – 72 grams for a standard bag, apparently.

Fantastic! Now you can divide the confusing grams per kilometre figure by 72 to get a more easily understood rating. So, the VW Polo Bluemotion emits 1.375 Walkers (99g/km divided by 72), the Mondeo diesel does 2.16 Walkers, while the Aston Martin DBS puffs out a weighty 5.8 Walkers. Then there is that weird and completely inexplicable German measure of fuel economy, litres per 100 kilometres.

Is 16.5 litres/100km a good figure, or is 6.5 litres/100km? I’ve got an alternative measure that anyone can understand. Pay cash for your fuel and check your wallet, then work out how many members of your family you can take out for supper at a Wagamama noodle bar with the remaining contents.

We’ll call the base unit (enough to feed one person) a Waga. At present, the 2.5-litre Ford S-Max I’m running is a 0.25 Waga car, although the diesel version of the same model is a 1.75 Waga motor. I’m also working on a new measure of internal car space that is based on suitcases. It’s called Samsonites, after the cases, and is based on how many Sammys you can fit in the back. So Fiat’s 500 is 2.5 Sammys, while Renault’s new Laguna is 4.7 Sammys, with a 2.5 Sammys boot. I’m open to ideas here, so let’s simplify this new year and invent some different motoring standards. What would you like to see made more straightforward?