Notes From the Hard Shoulder by James May Page A

His question concerns petrol consumption.
    Which is the more economical way to drive in town, he wonders: to accelerate briskly between sets of red lights so that you spend longer with the engine merely idling, or to drive gently between them, which would mean less time spent at the next lights but more time working the engine?
    Well, I like a bit of amateur physics and I think I know the answer to this one. The fact is – and it's one on to which most motorists have failed to cotton – that braking consumes petrol. In essence, the brakes work by converting the kinetic energy of the car (i.e. that which it has through motion) into heat at the brake discs. Maybe also a bit of heat in the tyres as well, if you've overdone it.
    If you overdo it a lot and hit a tree, some of the kinetic energy of the car will be converted into noise and an inflated insurance premium. But either way it has to go somewhere because, as we know from Newton, it cannot be destroyed.
    It cannot be created, either. So the kinetic energy of the car must have come from somewhere, and that somewhere is the petrol, which has energy locked in it waiting to be released by combustion and converted to motion through pistons and gears and what have you. So if you're thinking of braking heavily, maybe you should consider simply emptying a bit of your fuel tank on to the road and setting fire to it. At least you won't be wearing out the brake discs.
    Therefore the most economical way to drive between the traffic lights is to accelerate at such a rate that the next set will have changed to green just before you get to them, thus removing the need to brake at all. And there you have it. I believe that was a lot easier than some of the questions we used to ask Mr Snook about 'biology'.
    Unfortunately, this brings up a rather more sensitive question, namely, should we worry about saving petrol anyway? I think not.
    Every time I do the arithmetic I come to the conclusion that saving petrol is pointless. I know we now have some of the most expensive gravy in the world, but the cost of it still amounts to a hill of beans compared with the real cost of owning a car.
    This is true even of a supposedly depreciation-proof classic, as I have proved through scientific experiment with my old Bentley. It does 14mpg, and then only if I

drive like an undertaker, which makes it quite expensive to use. But maintaining it has ruined me, so the only real route to better economy is to get rid of it altogether. Trying to drive it economically would be fatuous.
    So the old adage that says 'if you can't afford the fuel you can't afford the car' is probably as true as it was when it was coined, which was when four-star cost three-and-six and most British people only had one pair of shoes.
    Here's what I honestly think. If you're the sort who regards motoring as a necessary evil, don't try to drive economically. Just buy a truly economical car, since they're generally cheap to buy and maintain as well, and drive normally. If you're a car enthusiast, forget the cost of fuel. Worrying about it is like an alcoholic drinking less to save money.
    Trying to save fuel is a truly false economy, and for proof of that considerWO Bentley himself. He advised that you should 'drive as if your brakes had failed', which I always took to mean 'drive in a gentlemanly fashion'. But now I suspect he was just trying to eke an extra few mpg out of a Speed Six.
    And what good did that do him, eh? A few years after he wrote that, he went bust.
    JEREMY CLARKSON RUINED MY DREAM CAR
    Regular readers will know that I'm a great fan of inventing new games with my TV colleague, TV's Richard Hammond. One of my favourites is calledAirport Shopping Dare, and here's how to play.
    It's really very simple. When you're at the Heathrow departure terminal with a chum and a few hours to kill, you will inevitably abandon every tenet of real manhood and end up walking around the shops together. Now you must spot something you