It's off if I'm going for mileage, especially if there are hills, and on if I just want to relax and enjoy the ride.
Cruise does just as well at highway speeds if the requirement is to maintain speed within +/- 1 mpg. Maybe even better because it does pulse and glide well. If I'm trying to maintain 68 mph and approach a hill and am willing to let the car slow to 64 mph on the up hill, then of course my manual method will give better results.
I get better MPG when the computer is driving ;-) ..... it has a lighter foot I think.. However in the UK the roads are usually so jammed that without a Radar sensor cruise I don't get to use it unless its an open road.
Cruise does just as well at highway speeds if the requirement is to maintain speed within +/- 1 mpg. Maybe even better because it does pulse and glide well. If I'm trying to maintain 68 mph and approach a hill and am willing to let the car slow to 64 mph on the up hill, then of course my manual method will give better results. ################################################# I'll second that.
with the hills in ECO mode, the CC seems to do better for me, but I'm not psycho about it. I went from a 19MPG Cadillac, 46 is fine for me.
I'm pretty sure the general rule of thumb is that cruise control saves fuel. Maintaining the same exact speed, and thus engine speed, is more efficient than a constant varying speed. However, the above posts are right, if there are a lot of hills, then the cruise will use full power to climb and maintain the speed.
Hills: Manual Flat: Cruise Economy: Manual Super Economy: Manual (P&G) Lazy: Cruise In practice, if there's a BIG hill i exit cruise, the rest of the time i leave it on.
Years ago, cruise made a big difference in highway mpg. Much better. But with my Prius, who cares? I get 50 mpg anyways. But it's more relaxing on long trips and straight roads with low traffic.
Hey mgb4tim, then you should put a Caddy badge on the back of your Prius and let everyone know how much better your mpg is. Like this (see avatar at left) PS - I used to have a 73 B, last year for the metal bumpers. Fun little cars. I have the grill badge from that too. Hmm..... naw, I didn't turn the B into a Prius. But I did turn my A4 into a Prius. And I considered making my 81 Alfa Spider into an electric car. But available tech last year was only good for 30 miles range.
Question is, which is the better way to get 68 (or whatever) miles in one hour: Plan A: On flat sections, drive 70 manually, but let it slow down on uphills to keep it in the Eco zone, and average something less than 70, say for example 68. Plan B: Set cruise at 68. Jury's still out, but I think Plan B is better.
I would make this more realistic by adding an option 'C'... Plan C: Drive around 68 mph consistently, but ensuring that your HSI indicator never goes above 75% (meaning about 1/2 way between the midpoint where the ICE normally turns on, and the top end, before going into 'red' zone). (This will cause you to slow down a bit on all uphills, and speed up on the downhills quiet a bit, but maintains similar engine 'rpm' as it were) This is what will keep the vehicle operating the most efficiently over a given course, as opposed to trying to keep the forward speed the same. This is how I try to drive longer trips and regularly maintain 60-63 mpg doing so.
