How are motorists saving fuel?
Petrol prices have risen to record levels and the UK government has hinted it may postpone a planned 1p fuel duty increase due next month. But how much have driving habits already changed in an effort to save fuel?
In 2000, fuel protests sparked by rising petrol prices nearly brought parts of the country to a standstill. The price at the pump was about 80 pence a litre.
Now, a little more than 10 years later, the price has broken the £1.30 ($2.10) mark, and people are responding in quite a different way. They are changing the way they drive.
It's not surprising that motorists are getting savvy in trimming their fuel bill, with the tank of a family saloon costing nearly £70 ($113), at a time when rising living costs are squeezing household budgets in other ways.
Chancellor George Osborne has hinted that a 1p fuel duty hike due next month will be scrapped, after the highest oil prices since 2008 sent prices at the pump to record levels.
But motorists are not waiting for help, but helping themselves. While eco-driving has long been favoured by those keen to trim their budgets or reduce harmful CO2 emissions, the steady increase in petrol prices over the past year seems to have influenced habits more widely.
One key change appears to be that people are making fewer journeys, although how much is due to fuel consumption is difficult to say.
Figures supplied by the Department of Transport suggest that congestion on motorways and trunk roads has been falling. In the year ending December 2010, the provisional figure for average vehicle delay on the slowest 10% of journeys was 3.55 minutes per 10 miles, a fall of 9% since March 2008.
Adrian Tink of the RAC is in no doubt that motorists began cutting their driving towards the end of last year, as they felt the pinch. In a survey of 1,500 drivers last month, 75% said they had reduced car use.
"We're seeing record levels of people walking and biking. Evidence from the last couple of quarters is that sale of petrol is dropping. People are buying less fuel.
"A lot of people are combining journeys and making shorter ones. Instead of popping out twice they are popping out once. People are doing fewer longer journeys, because they are looking at alternatives like the train."
They are also driving more slowly, he says, with anecdotal evidence that average motorway speeds are down.
"We have a lot of patrols and customers contacting us and it's absolutely clear that people are changing their habits because they need to reduce the money they're spending on the tank."
Fewer car journeys means less pollution, fewer road accidents and shorter traffic jams, all of which would be welcomed my many.
It's a point Mr Tink is happy to acknowledge. Economising is not a bad thing, he says, but there's a danger that people are being priced out of their cars, in a society that for 20 years has been designed around them.
The AA reports the same picture, of falling petrol sales and fewer car journeys. Spokesman Luke Bosdet says petrol sales in the third quarter of 2010 were down by 13% compared with 2007.
"We do surveys of 15,000 AA members and two thirds say they're cutting back on car use or reducing other household spending to absorb the extra costs.
"Our research suggests people are cutting down on motorway speeds and sticking to the slower lanes. There's a degree of danger in going too slow if lorries come up behind you. But drivers that might have done 80 are now doing 70 and that means a significant saving."
A rule of thumb often followed is that 50-55mph is the optimum speed, says Mr Bosdet, but it depends very much on the car.
Driving at 80mph will cost you about 10% more in fuel than driving at 70mph, says a spokeswoman for the Department for Transport.
This week, the use of speed limits as a tool to control fuel consumption was highlighted in Spain, where the speed limit was reduced from 120km/h (75mph) to 110km/h (68mph). Spain is heavily dependent on imported fuel and 13% of its oil usually comes from Libya.
One family in Exeter has been putting these principles into practice. The Boults have saved 54% from their fuel bill since last summer, which amounts to an annual saving of £619 for the two-car family.
Some of that saving is down to cutting down on car journeys, says mum Heather, a 42-year-old community centre manager, but about two-thirds is because of changes to the way she and husband Martin drive, after some eco-driving lessons from Shell as part of the Shell Smarter Drivers Initiative.
"There were little things like putting more air in the tyres. And I had always felt it was good to fill the tank but if you half fill it then the car is lighter and you use less fuel.
"I used to pull up at traffic lights and think they would go green in a little while, and leave my feet on the clutch and accelerator, but now I put it into neutral, the handbrake on and take my feet off the accelerator, which can save you about £10-20 a week.
"And driving more smoothly is important. The more you are pressing the accelerator pedal, the more petrol you're running through the car, so if you keep it at a constant speed, at 40mph instead of 50, 30, 60, 20."
Leaving about 10 minutes earlier for work, before 8am instead of after, means avoiding traffic jams and driving with an empty boot helps too.
Behaviour at the petrol pump has changed too, according to research by Asda supermarket. Based on thousands of transactions nationwide in the two years leading up to January this year, there was an increase of 18% in the number of people filling their tank only to a round pound, like £10 or £20, not to the full tank.
And the average spend at the pump has fallen from £25 to £20, says the Retail Motor Industry Federation, and more customers are paying with cash and coins.
It's all part of a cultural shift which has made fuel consumption a subject now regularly heard at dinner parties, says Maria McCarthy, author of The Girls' Car Handbook and proud owner of an N-reg Vauxhall Astra.
"Since January it's been the number one issue. The big discussion is how long can you make a fuel tank last? People are starting to talk about it like they used to talk about property prices.
"In my line of work, people in social situations don't usually talk to me about my work, but now they do. We have these cultural shifts and they recently reached a tipping point and everyone is now concerned about fuel consumption."
Some motorways have taken on an eerie quiet, says motoring expert and broadcaster Quentin Willson, speaking while driving.
"We're going a lot slower, we're not doing... the pleasure journeys. I'm currently on the M6 [motorway], it's three o'clock and it's absolutely clear. I'm doing 70mph and it's fine.
"Last night, I was on the M20 and it was eerily quiet. So I think we're seeing a real change. People aren't driving, doing the stuff they used to do, because they're saving fuel."
While environmentalists would welcome reduced car use and reduced CO2, says Willson, it also means reduced VAT, corporation tax and money to the Treasury. The implications of a further rise in fuel duty would affect all aspects of the economy, increasing prices in general and ultimately costing jobs.
Long-term, the solution lies in greener technology. "Fuel efficiency has changed what we buy. Straight off the showroom carpet, you can buy a Polo Bluemotion, which does 70mpg and a little Vauxhall Corsa which does 60mpg.
"For the last four or five years, the car industry has seen this coming. We'll have a 100mpg car before long."