Cruise control VS fuel mileage

I would like to get some opinions on how effective it is to save fuel by using cruise control on the highway. I have an opinion and would like to share it. Any argument is welcome.

I live in the state of Maine. We have a lot of hills around here. If I use cruise control, my vehicle is doing its best to keep up with that exact speed at all times. When you go uphill, the vehicle will most of the time downshift to the next lower gear. What happens if I keep my foot at one spot on the accelerator, just enough to keep it going the same speed on flat ground? Obviously if I start going uphill, i will lose some speed, maybe 5 or 6 miles per hour before it downshifts to the lower gear. But once I get to the top of the hill, the transmission will go back into the high gear, and resume back to my speed from before.

Now it seems to me that if this is the case, I will be getting slightly better fuel mileage, because the engine is working a little less harder. Does this sound logical to anyone?

I own to Fords and the owners manual of both vehicles states that using the cruise control in hilly country will decreasee you gas milage. I have experimented with the cruise control while driving in the hills and noticed a significant drop in MPG.

Cruise control will always due its most to maintain the same speed it is set at. That is the only thing it will do. So, it is set at 70MPH and you go up a hill, it will put the pedal to the metal to maintain that speed. With you in control, that won’t happen.

Yes Cruise control will reduce your gas mileage. Best gas mileage though illegal for speeding reasons is to see what the truckers do. Up to 75 downhill, down to 55 uphill. Forcing the engine to slow the vehicle costs fuel, forcing the engine to speed the vehicle costs fuel. Go with the flow and enjoy better gas mileage.

Cruise control is meant for reasonably level roads in light or no traffic. Using it in hilly country will lower your gas mileage. Using it in traffic is dangerous!

Cruise is a convenience feature to reduce fatigue on long trips. It was not orignally designed to save gas. Having said that, on level roads it does save gas.

I set it at 62mph then just before hill I speed up to 70 and let up slowly going up. Do this and alot of hills it will not down shift.
I have foot trouble and need to use criuse, also if you have a power button on aout trans leave it off on hwy

One of my best tanks in my wife’s Honda Element netted 30 mpg using cruise control in the mountains near Taos NM. I just click the cruise control off if I see a climb that’s likely to make the transmission downshift to maintain speed and then hit resume after the hill is behind me.
I like cruise control because it has better speed limit obeying disipline than my right foot does and thus saves me from speeding tickets.

Cruise control even in the hilly East Bay area can return up to 60 mpg on a Prius.

It is a good idea to kick off the cc when approaching a hill and manipulate the throttle yourself.

Sure, if you are careful, attentive and know how to most effectivly to manually control your speed, you will do better than cruse. Likely a fair amount better in your area. However many people don’t have a clue and cruse control for them would likely result in better mileage.

Where is “East Bay”?

That’s true, but I’d hate to be driving behind you.

It sounds logical and will probably save gasoline if those were the only conditions. Most people can’t stay alert enough to do a good job under all conditions. Short trips usually work out better without cruise control. Opinion only.

That’s true, but I’d hate to be driving behind you.

Good point. Anytime you are driving, you need to be considerate of the other drivers. Part of that means you don’t drive slower than the speed limit, if you would be delaying other drivers or causing other safety issues.

I draw the line at the legal speed limit, I don’t feel obliged to drive over the speed limit because someone behind me would like to. However even then, keep in mind they may be a crazy and maybe it would be best for you to do everything possible to let them get around you.

For the most part interstate highways are built to standards that minimize the climb angles so big trucks can maintain speed. Local highways have steeper climbs, and some mountain areas there is just no way not to have a steep grade. On interstates I usually use cruise, traffic permitting, and probably get better mpg than if I controlled the gas manually. On local highways at 55 mph in hilly country it is better to go manual with the gas.

The fuel savings of cruise is not that big a deal. I like it so I can set a speed that is fast enough to make good time and not put me at risk of a speeding ticket. I’m not interested in a radar device flashing and beeping at me as I motor along.

When towing the cruise is off and I use the momentum coming off the downhill to help me with the uphill climbs.

Forcing the engine to slow the vehicle doesn’t cost fuel. downhill in 3rd at 4000RPM uses less fuel than the same hill in neutral at 700rpm.

I strongly recommend not trying to keep your foot in the same place on the gas pedal and letting the car slow down and speed up. This will drive the people behind you crazy and you just may cause road rage. And some other innocent victim may be the recipient of that anger.

Safety and courtesy toward the others with whom you share the road are more important than mileage.

Professional drivers, trying for the best possible fuel economy, will gently accelerate going DOWNHILL letting the hill add to the stored kinetic energy, and then gradually decelerate going UPHILL, letting that stored energy (instead of more fuel) push the car up the hill… Cruise control can’t do that.

Absent a reply from GSN fan, I think this East Bay is the area east of San Fransisco Bay (Oakland, Alameda County, and what-all).

I can accept it from a tractor trailer, but in a car it drives me crazy.

Imagine if you will a long line of cars each doing this in a hilly area. As the car that just starts up the incline slows down as the ones behind it coming down the previous incline are speeding up. Then as the car in the lead goes over the incline and speeds up, the one’s behind are still slowing down.

Yes, that is where I was talking about.