Reducing the cost of motoring

Or "Another of Martin's Bright Ideas".

Again, throught the internet I keep hearing how the cost of petrol is going up and up in the UK and in America (the last time I went home, petrol was aroun 99p per litre). It is no different in Japan. When I first got a car two years ago, I would be paying around 115yen (55p) a litre. At the moment, it's around 145yen (70p) a litre. Obviously a 27 percent increase over two years is way above inflation and I've been trying to think of ways to reduce the cost. I'm running a manual-gear kei-car, and with it's 0.6 litre engine I doubt I can get a car with better fuel efficiency. It runs on petrol, so I have no hope of running on bio-diesel or chip fat. I'm keeping my journeys in the car to a minimum; if it's in Tokamachi town centre, I use my bike. But there are always journeys I can't avoid; Monday and Wednesdays in Tsunan (35km/21 mile roundtrip), Tuesdays in Kawanishi (12km/8 mile roundtrip), footy training, events etc in Niigata (180km/112 mile roundtrip). So is there a way to reduce cost for those trips?

There is a way: stick to the speed limit. Everyone knows that the faster you go, the more fuel you use, and that rate isn't linear but exponential (i.e. fuel economy at 80km/h is more than twice that of 40km/h). But how big an effect is it? Well, on my trips to Niigata if I drive around 120km/h on the expressway, the roundtrip would need a full tank of fuel. If I drive at the speed limit, 80km/h, I use only HALF a tank of fuel on the roundtrip. "Oh but Martin, it would take a lot longer to drive at 80km/h." Actually, it doesn't. A single journey from Tokamachi to Niigata at a top speed of 120km/h takes about 1h 15 min. A single journey from Tokamachi to Niigata at a top speed of 80km/h takes about 1h 30 minutes. So, a saving of half a tank of fuel (1,800 yen / £8.50) for an extra 15 minutes driving. So on employment terms, I'm getting paid 7,200yen/£34 an hour to stick to the speed limit. It's so simple I can't believe I hadn't thought of it before.

And when I reduce the amount of money I need to spend on petrol, it also means that I'm reducing the amount of emissions I'm creating, so both my Dirty Northern Bastard and my Green Inner Geek are happy.