Does Cruise Control give better or worst MPG (1 Viewer)

[Dorset Diver]

Only some cruise control units are connected to the brakes. This is far more likely on a factory fit system where the manufacturer gets to design or specify the entire system, including the brakes. Retrofit systems are less likely to have braking capability as this requires integration with the complex ABS systems (unless the "retrofit" system is just adding the missing stalk to the pre-existing manufacturer system). Without this braking ability, the vehicle will gain speed going down steep hills.

Every Adaptive CC I have driven has been connected to the braking system. CC is not as it has no means of knowing what is happening in front of the vehicle. Are you confusing the two?

 

[cmcardle75]

Ive never yet had a vehicle with cruise control that was fitted to the brakes , my vw T4's , passat cc , merc e220 , bmw 520 , 318, 328 all simply used the engine braking .... certainly none activated the brake lights......i think ACC is fairly new and may be different as it will automatically guage the speed of vehicles in front etc .... none of mine ever had that but the newest vehicle ive had was a 2013 Renault captur.
None ever activated the brake lights when on cruise but none ever went above the set speed either as thats pretty much the job of cruise control to maintain the set speed.

Thats why i made the comment as this is the only vehicle ive ever owned that the speed increased going downhill while on cruise control.

But it is the only one with retrofit non factory supplied cruise

I fitted cruise to 3 of my t4 vans but simply a case of fitting and plugging in the stalk and then activating via ecu

Yes, I've only had brake assisted cruise control on more recent cars than 2013 and they've all been adaptive. However, without a connection to the braking system, any such system is susceptible to overspeed on steep hills unless they are able to increase engine braking somehow, such as getting the transmission to change down. The energy has to go somewhere.

 

[cmcardle75]

Every Adaptive CC I have driven has been connected to the braking system. CC is not as it has no means of knowing what is happening in front of the vehicle. Are you confusing the two?

No. Whilst adaptive cruise always has braking connection, non-adaptive cruise can have braking connection, but often doesn't. Obviously such a system can't brake for cars in front, but it is able to maintain speed on downhill sections.

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[Gaston aires]

I don’t think about MPG, with sciatica, I wouldn’t leave home, or buy a vehicle without cruise control.
Phil

 

[Jake Royd]

I have a VW Passat with adaptive cruise and it's fantastic, use it all the time on the motorway.

My Ducato based motorhome also has standard (non adaptive) cruise.
Again, I use this all the time on a motorway but my reason for this is more about the throttle being very lightly sprung , so holding my foot still for hours on end makes it ache like hell.

 

[Northernraider]

Yes, I've only had brake assisted cruise control on more recent cars than 2013 and they've all been adaptive. However, without a connection to the braking system, any such system is susceptible to overspeed on steep hills unless they are able to increase engine braking somehow, such as getting the transmission to change down. The energy has to go somewhere.

Well that was my point as none have ever increased speed going downhill and that includes my T4 multivans towing caravans in the Highlands of scotland if i set it at 60 it stayed at 60 never increased.
This is the only vehicle ive ever experienced it on and i must have easily had 50 -60 vehicles with cruise control fitted.

They also returned to the set speed fairly quickly if you had accelerated to overtake and then lift off but this takes a few minutes to do it.

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[cmcardle75]

Well that was my point as none have ever increased speed going downhill and that includes my T4 multivans towing caravans in the Highlands of scotland if i set it at 60 it stayed at 60 never increased.
This is the only vehicle ive ever experienced it on and i must have easily had 50 -60 vehicles with cruise control fitted.

They also returned to the set speed fairly quickly if you had accelerated to overtake and then lift off but this takes a few minutes to do it.

Perhaps you always used to drive manual cars with large engines in low gears and the new car is an automatic and chooses a much higher gear with much less engine braking?

 

[poppycamper]

Ahh Poppycamper welcome aboard at last, I am so please you have finally grasped the point that if you set 70mph on your Adaptive cruise control you will only travel at the speed (providing of course it doesn't exceed 70mph) of the vehicle in front of you.

Now to shed light on your confusion, No a vehicle with Adaptive C C will not see another vehicle coming from the right on a R-A_B.

So back to my E.G. as you approach the R-A-B with your Adaptive CC set at 70MPH you vehicle has registered that the car in front of you is slowing down thus your car will also slow down, keeping that safe distance between you both that had previously set in the vehicles settings.
Now then the car in front at the last moment without any warning or indications moves in to the right hand lane, your Adaptive CC instantly recognises that it has a clear road ahead.
Now then here's the rub......your car oblivious to the R-A-B and indeed also oblivious to the car that is currently on the R-A-B will unless you take evasive action collide at some considerable speed with both.

That's the thing about an automatic vehicle, they are automatic but you have to be there in an overall controlling position.
Hence me mentioning you have to be pro active.

I trust this clarify's the situation for you.

So at what point would you be proactive????? Before or after you plough into the car your marvellous cruise control did not see. ????

 

[Northernraider]

Perhaps you always used to drive manual cars with large engines in low gears and the new car is an automatic and chooses a much higher gear with much less engine braking?

Always in top gear when using cruise control ...this is a fiat ducato manual motorhome

The only 2 i had that were autos were the Passat cc and the bmw 328 the rest have all been manual.

But never used cruise unless in top gear , mostly motorways or 50 ,60 limits ...never used it in 30,40 zones

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[poppycamper]

Always in top gear when using cruise control ...this is a fiat ducato manual motorhome

The only 2 i had that were autos were the Passat cc and the bmw 328 the rest have all been manual.

But never used cruise unless in top gear , mostly motorways or 50 ,60 limits ...never used it in 30,40 zones

My retrofit cruise has two settings you can permanently set two different speeds.... I have 30mph and 40mph set so if I am on an appropriate 30/40mph stretch of road i engage correct gear and engage cruise.

 

[Vipar]

I have better things to worry about.
But I like the cruise control on motorways and the limiter in speed controlled road works

 

[Northernraider]

My retrofit cruise has two settings you can permanently set two different speeds.... I have 30mph and 40mph set so if I am on an appropriate 30/40mph stretch of road i engage correct gear and engage cruise.

Ive found in the uk most drivers are incapable of maintaining a steady speed at 60mph never mind on slower roads not including roundabouts , traffic lights etc etc so i couldn't be bothered with having to constantly set and reset cruise control.

I use it when im doing long distances at steady speeds thats it

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[RobL]

I use it all the time in the car when possible. I can't say it affects mpg just a more relaxed drive.

 

[cmcardle75]

Ive found in the uk most drivers are incapable of maintaining a steady speed at 60mph never mind on slower roads not including roundabouts , traffic lights etc etc so i couldn't be bothered with having to constantly set and reset cruise control.

I use it when im doing long distances at steady speeds thats it

That's why adaptive cruise is so much better.

 

[robnchris]

So at what point would you be proactive????? Before or after you plough into the car your marvellous cruise control did not see. ????

I'll leave that for you decide if and when you want to take evasive action, answer to me is pretty obvious.

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[Skez]

So at what point would you be proactive????? Before or after you plough into the car your marvellous cruise control did not see. ????

poppycamper I don't really get your point. The driver remains in control of the car at all times. Adaptive cruise control, cruise control, speed limiters are just driver aids, there to be used or not, and when necessary over-ridden by the driver who is the decision maker in whatever vehicle they are in control of.

 

[robnchris]

poppycamper I don't really get your point. The driver remains in control of the car at all times. Adaptive cruise control, cruise control, speed limiters are just driver aids, there to be used or not, and when necessary over-ridden by the driver who is the decision maker in whatever vehicle they are in control of.

The salesman said the car is an automatic.....
So he got in the back seat.....

 

[Sundowners]

It is not an issue with our 'new' 1991 fiat but on previous motorhomes I think I could get better MPG without it but certainly not enough to be an issue------ biggest advantage for me is maintaining speed at village speed limits, especially in france where they sometimes go on for ages and soooo many speed cameras!!!!!

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[gus-lopez]

Brake light switch is linked to brake pedal

& as soon as you touch the pedal the cruise drops out.

Every Adaptive CC I have driven has been connected to the braking system.

& must operate the brake lights then?

But never used cruise unless in top gear , mostly motorways or 50 ,60 limits ...never used it in 30,40 zones

I do . Mine won't do 50mph in top gear & the cruise also drops out below that speed in top.
Through France on A & N roads I drive for hours not in top with the cruise engaged.

 

[cmcardle75]

& as soon as you touch the pedal the cruise drops out.

& must operate the brake lights then?

I do . Mine won't do 50mph in top gear & the cruise also drops out below that speed in top.
Through France on A & N roads I drive for hours not in top with the cruise engaged.

I would presume the cruise control would operate the brake lights (but you don't get to see them when driving). It would be dangerous otherwise. It is capable of sticking on quite a lot of braking when the car in front stops suddenly.

I would prefer to see some sort of indication when it is braking, though. I don't like the thought of brake fade as it descends hills. I often turn it off on long downhills to be sure it isn't dragging the brakes all the way down.

 

[DMC65]

I don't have a MH yet but I've had cruise control in my last 4 cars. I don't think there is much in it depending how you drive. I now have a Toyota self charging hybrid and would say the CVT almost teaches you to drive more gently and it's definitely better on fuel, hybrid aside. So I'd imagine your driving habits would have more to do with saving fuel.

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[Happy1]

Adaptive stopped my car in time to not plough into the four car pile up in fog the other day, it’s the way forward but at a cost.

 

[Bossman Bluey]

When I picked up my 2004 burstner the owner didnt even k ow it had cruise control!
I'm with the consensus here is far more relaxing, reduces , cramp , I would not be without it!

 

[bexleyjohn]

I have a 2016 2.3lt Fiat Ducato in a 3.5tonne Dethleffs. I use cruise control as often as practical and have travelled throughout the UK and across Europe. I set the cruise control on max 60mph but accelerate when needed beyond that.
In the four years since new I have averaged 27mpg (I keep a log) - that’s measured by both actual diesel usage and according to the on-board computer. I think that’s pretty damned good.
Interesting to note the on-board computer on my Motorhome is the FIRST I’ve ever had in ANY vehicle that is accurate to 0.5 mpg.

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[Camdoon]

Adaptive cruise control still has a number of issues. As already mentioned the driver in front moving out your lane unexpectedly, found that at a roundabout once; when on a dual carriageway you let a faster car doing 70 go past when you are doing 60 but the system then recognises the car in front of you is doing 50 so slows you down as you move out to overtake when you want to maintain speed which is no fun with a low powered high geared manual; on a 3 lane motorway you are in the inside lane doing 60 a car in the middle lane is doing 70 and overtakes you, you assume that he will continue to do 70 as you want to overtake so check your mirror but he is a middle lane hogger and does not overtake a car doing 65 in the middle lane as it is easier to let the adaptive control the speed rather than move out to the 3rd lane, you see this quite often in multi lane roads; the gap left by adaptive cruise control will have you going backwards on the Paris peripherique/morning m25.

 

[Mike Rivers]

You will ALWAYS achieve better mpg using cruise control. I drive approximately 100,000 miles a year and am constantly surprised to see the fantastic mpg returns on some modern cars and vans. The secret is constant speed and avoiding hard acceleration. When the vehicle is in cruise control mode the fuel is being meted out far more efficiently than your right foot can ever hope to achieve. However, you need to develop a driving style where you anticipate having to slow down thus ‘pausing’ the cruise as opposed to using the brake and getting into the highest gear (lowest revs) as early as you can sensibly. Our Bailey 75-2 (3500 kg) regularly achieves 31-32 mpg over a mixture of A roads and motorways. The previous post mentioned adaptive cruise control where your vehicle has a habit of latching onto the slowest vehicle on the motorway in which case achieving a constant speed is nearly impossible!

 

[Keith E]

I recently read an article which explained in depth-with graphs and pie charts and other scientific gubbins-how cruise control is less economical.
Whether I believe it or not, I'll still use my cruise.
It makes life easier.

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[Dorset Diver]

As I said somewhere above my wife can always get better mpg driving manually than with ACC, I can't and it is very very annoying.

 

[two]

Just wondering your thoughts on MPG when using or not using cruise control? My MH does not have it, but my car does and I think I can better mpg when not using cruise control.

It all depends on the base-line. An alert driver should be able to do better than an automated system because the system is not as 'smart' as the marketing people would like you to believe. I think thee are a few CC systems linked to GPS, to try and anticipate bends, hills and such but a driver will be noticing many other factors that the CC designers haven't even thought about or can not get the data for (lights changing, road restrictions, ...).
Whilst I have little time for Cruise Control, I encourage those with a Speed Limiter to try it out (except on Fiat). There's still room for improvement (why do they index by 5 units, not 10?) but they've saved me a few potential speeding fines.

 

[Jaws]

I use cc all the time.. it allows concentration on the road instead of the speedo esp. in built up areas
A couple of years ago I made a conscious effort on a run to Spain NOT to use the CC at all and saw a marked improvement in MPG
But as others have said, in the over all scheme of things the exercise proly saved me about 4 gallons over the 1350 miles..
For the effort I did not think it worth it ( and I am a tight git ! )

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