Slower driving can save motorists £500 a year

[Poppycat]

Slower driving can save beleaguered motorists more than £500 per year, according to a study that suggests that the most fuel efficient speed can be as low as 20 miles-per-hour.


Tests on five different cars ranging in size from a 1 litre Toyota Aygo to a 2.2 litre Land Rover Freelander found that the most efficient speed was below 40 mph for all five and as low as 20 mph for two.

http://www.telegraph.co.uk/news/2109539/Fuel-prices-Slower-driving-can-save-motorists-and163500-a-year.html

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[Hintza]

It's all just too depressing, I managed 16.2 mpg last night with the horsebox on.

Interesting article, but travelling at 20mph? Must have done that in the lab or Norfolk the first slight hill would soon change those figures.

[Conor]

Not driving at a reasonable limit for the road conditions can see you being charged for driving without due care and consideration for other road users and it certainly isn't saving money for a lot of people.

[Lakeuk]

Well for the past few weeks I've changed my driving habits in the following ways that has resulted in me getting 12% more miles out of a tank of petrol and only added an extra few minutes to each hour driven:-


On motorways reduced speed from 70mph to 65mph
pull out earlier to help maintain speed, avoid speeding up/down
When coming to junctions let the gears slow me down (used to use neutral plus brake) and try not to come to a complete stop so easier to pull away

[anewman]

Is this diesels or petrols as well? I'd say the slowest acceptable speed on the motorway really is probably 56mph behind the lorries. I would imagine many older cars, particularly petrol, wouldn't see the amazing MPG gains mentioned anyway when going at 40mph.

[tomstickland]

I've managed a 20% improvement without resorting to 20mph road blocking.
60mph on A roads, 70mph on motorways, just plan ahead more carefully.
Travelling up one of the hills I will see better economy if I carry some speed up the hill, at around 45mph, wherease if I'm stuck behind something that's slower the mpg is worse.

[bicycle_repair_man]

It's not really the speed you're driving at that affects fuel, it's the amount of revs you're doing, so best thing is to make sure you're in the right gear.

[Poppycat]

But if you are in right gear and dont go to fast then surely thats saving money

[kitchpoo]

..... Must have done that in the lab or Norfolk .....

We do have hills in Norfolk, well some parts of Norfolk anyway.

[BenL]

I read somewhere about not letting your car rev above 2000 rpm when accelerating is good for economy (less revs makes sense).

This is quite hard to do, most of the time i'm not out of a junction and have to change gear from 1st and this policy is shot when i am in 5th as its 43 mph.

[tomstickland]

It's not really the speed you're driving at that affects fuel, it's the amount of revs you're doing, so best thing is to make sure you're in the right gear.
The speed does make a difference, because it's the work to overcome drag forces that takes up most of the output power in steady cruise.

[BenL]

Another thing learnt this morning on the radio. I had wondered but someone else has figured it out.

Upto 40mph use open windows for cooling

Over 40mph use Air Conditioning as its more efficient using than the extra drag placed on the car by having open windows.

[Conor]

I travelled from Driffield, East Yorks to Grangemouth and back keeping to the legal limits and managed to return 60.3MPG out of my 2L Mondeo TDCi which is 3-5MPG more than usual however I did manage to find the opportunity to use 6th gear which I normally don't. Driving slower (came back via A1 whereas on the way up I used the M74) at 60MPH instead of 70MPH made no noticable difference.

[Tozer]

I read somewhere about not letting your car rev above 2000 rpm when accelerating is good for economy (less revs makes sense).

This is quite hard to do, most of the time i'm not out of a junction and have to change gear from 1st and this policy is shot when i am in 5th as its 43 mph.

It will totally depend upon the car. You will labour the engine if you are in the wrong gear and the revs are really low which could cause damage....and will use a lot more fuel.

Car manufacturers tend to fix the engine management systems at between 50 and 60mph for max fuel efficiency. Hence the best economy mpg is usually quoted at 56mph (100kph).

[Poppycat]

I have heard you can get you engine management system in the car altered for speed or economy

[Tozer]

I have heard you can get you engine management system in the car altered for speed or economy

True. But you will probably invalidate the warranty.