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I'll go for a qualified "yes" with this. Since I fitted mine I can see an improvement in general, but not a lot.

The trouble is that it's only really useful on motorways & empty roads. In traffic you keep cutting it off by using the brake and if you use 'Resume' you find the old speed won't match the new speed of the traffic.

The other tendency is to try and keep a steady speed on bendy roads. If you've set too high a speed and try to hold on as long as possible, you end up braking hard and late in most bends.

So , I think 'yes' as an aid to smooth driving, but in difficult conditions you could equal or better it my doing it yourself. Otherwise you end up with more work pressing the up and down buttons.
 

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And just for the other side, I'll add a qualified "no".

Given that the objective of cruise control is to maintain a steady speed because that any extra acceleration uses more fuel etc, it should in theory be more economical. However, it relies on a clsoed loop feedback system that has a finite ability to react. In effect it has to spot that you've dropped slightly below you current speed to then correct it (ie accelerate). A skilled and concentrating driver however, does this much better and also has that advantage of being able to see what's coming next in terms of hills etc and anticipate more accurately when to either apply a little bit more pedal pressure or back off.

(Edit) Qualification:
However, given that if you use it you're generally speaking more likely to maintain a constant speed because frankly we do wander about- I know how frustrating it is on the mway to keep playing "leapfrog" with drivers that aren't using cruise then yes, it should save you fuel.
 

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I'm with Bubbles on this. I find that my cruise has a somewhat heavier "foot" than I do, the speed varies more noticeably than when its my foot on the pedal.

But on a long run its nice to be able to take both feet off the pedals, tilt the seat back and close your eyes for a few minutes
 

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Originally posted by Gassy 248+:
[qb]But on a long run its nice to be able to take both feet off the pedals, tilt the seat back and close your eyes for a few minutes   [/qb][/b]
Of course, this is quite possible to do safely if you are a regular commuter on the >insert preferred road name<, when all you need do is put the handbrake on and wait for the "helpful" toot from behind...
 

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I find that I use the cruise control as often as possible. It does seem to give better mpg , probably because with me at the controls i get bored on way home/want too get home ASAP and there we are again at 95 mph, which isn't best for the mpg or for my licence.
 

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Discussion Starter · #9 ·
That was interesting, I think I am of the no camp, I agree with Bubbles the system is unable to identify a gradient until it detects changes in the vehicle speed due to gravity, hence more frequent need to increase fuel flow. As has been said, the driver can see ahead & anticipate what is required.
I posed the question because I rarely use cruse control, but travelling long distance on the near empty French autoroutes this year (joy) I did make use of it to give the accelerator foot a stretch. On downhill sections the system slowed the car to maintain the set speed, which necessitated a greater fuel demand as soon as the rising gradient was detected. There again any change in fuel consumption is probably academic.
 

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Instead of this conjecture, why not conduct an experiment on your regular journeys? It seems to be fairly easy to get the EDU to measure your MPG and to reset it so you could compare the consumption using cruise and without. A few samples would prove it one way or the other for you.

Academic? I calculated that 1 MPG difference in average consumption on 25,000 miles per year equates to ~£96 at current petrol prices or less than the price of one pint a week. Go on put your foot down!
 
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