There’s been no shortage of noise about the Toyota Prius. Is it as economical as they say? A couple of years ago the popular British motoring show Top Gear did a segment in which they took a Toyota Prius and drove it around their track, with a BMW M3 driving behind it. They drove it ‘as fast as possible’, but this doesn’t mean flooring it (which would eradicate the Prius’s fuel efficiency).

In fact, with all the twists and turns on that track it’s actually quite a good simulation of real-world driving. You do more braking and turning than accelerating, and probably never reach the kinds of speeds you would on the average motorway.

The result? The Prius managed a respectable 17.2mpg – still far short of its advertised 50mpg. The BMW M3 (a high-performance racing car) did 19.4mpg.
Now, this isn’t the whole story by far.

An M3 is more carbon-intensive to produce than a Prius, but when you consider what goes into the making of a Prius battery alone, this difference is negligible considering that when you sell your M3 and buy a Prius, someone else just goes and buys your old M3.

More to the story

The message here is not that the Prius is inefficient. The message is that how you drive makes more difference than how much fuel your car uses as its baseline. If you are constantly accelerating and braking, instead of trying to keep as level a speed as possible, and you accelerate up hills, rev high when you take off, and drive in the wrong gear, you’re going to use more fuel regardless of what car you drive.

The sad truth is that most people have no idea how to drive economically, and so it doesn’t matter whether their car is powered by half-battery, half-fuel or a plutonium reactor.

Before we get onto which cars are really good for the environment, here are a few tips for driving more fuel efficiently:

• Always use the right gear.  If you have to put your foot down to slowly get the revs up, you’re using too much fuel.  Remember that the amount of fuel you’re using is directly proportional to how hard you’re pressing the accelerator.
• When approaching hills get your speed up as high as possible before the hill.  When you get to the hill keep your accelerator position constant.  You’ll lose a bit of speed, but use the minimum fuel.
• When going downhill put your car in gear (not in neutral) and take your foot off the accelerator.  Fuel consumption drops to zero. (Don’t do this with an automatic – you may damage the transmission)
• Keep a constant acceleration whenever possible.  If you’re one of those drivers who is constantly speeding up to close a gap in front, and then slowing down again creating one, you’re not only using as much as 30% more fuel, you’re contributing to ‘concertina effect’, which is the number one cause of traffic jams and there is surely a place already reserved for you in hell.

And if you Really Want to Save the Environment?

Buy diesel. Diesel cars are leaps and bounds more fuel efficient, and have far lower emissions, than their petrol counterparts.  The BMW Mini Cooper Diesel (blisteringly fast), the Smart Fortwo CDI (kind of cute) and the Volkswagen Polo Diesel (Car of the Year 2010) all have much greater fuel efficiency than the Prius, have lower emissions, are much less expensive, can be converted to biodiesel, have a far lower carbon footprint to manufacture – and are far nicer to look at and drive anyway.

The Verdict:

The Toyota Prius is a marketing gimmick and a guilt trip disguised as a green car (which some would say is an oxymoron anyway).  If you want your commute to have as little impact on the environment as possible, the Prius is one of the worst (and most expensive) ways to do it.

And the best way to save the environment?  Take the bus.