Does cruise control save gas?

It saves gas, since you’re not accelerating. Keep using it, unless you’re going up and down hills.

Yes, it saves gas. Why would you suspect otherwise?

@pete: Thanks man. :)

@steve: I didn’t necessarily suspect otherwise, I just didn’t want to continue operating under a false assumption, especially when it concerns the price of gas. I don’t care how low it goes, I’m pinching the crap out of those pennies.

Compared to normal driving? Yes. Compared to hypermiling? No.

Depends, actually.

On primarily level terrain, it certainly does. In hilly regions, it typically worsens economy because it isn’t adaptive. For instance, if you’re coming down one hill and approaching another, you’ll save gas by picking up some speed going down and slowing down going back up. Cruise control will limit your speed going downhill, using the engine’s inertia to slow the vehicle (more noticeable with a manual transmission and at high speed), then wait until the car slows down going back up the next hill before applying the accelerator.

Your engine will be doing more work because it’s already lost speed and has to make up for it, since cruise control is telling the vehicle to speed up. If you were working the pedals in that case, you could do better by either gradually slowing down once you’re on that hill or letting the vehicle slow itself down from the speed you picked up going down the previous hill.

Basically, since cruise control can only react to what the engine’s doing, it’s not as efficient as thinking ahead. But only when the road’s not level, like it is here in West Virginia.

I drive in West Virginia. Some autos are better than others. The cruise on a 528i is so precise in conjuction with the low end torque the cruise always saves gas. Smokies or no.

Lucky you, no cruise in my 325! It’s not a huge difference, but over the life of a car it’d add up.

@Joey I agree w/ you…in my car it is not adaptive. It is narrow minded and will “gun” the engine to get up to speed when you may normally allow your car to vacillate on hills.

On flatter highways w/out much traffic is the best.

I have observed great variability between different cars’ cruise control systems…
I even use it in 25 MPH zones to avoid tickets. Keeping a clean driving record in NJ is more important to me, especially since my Mini Cooper S is averaging 31 MPG.

I love me some cruise control. It’s true, though.. I live in WV now and my older car’s (‘93 Subaru) cruise control can’t keep up with the hills, typically. I always wondered about this whole cruise control issue, and now I know to help the car out by allowing it to accelerate down hills before going up another.