actually, you're wrong. The only reason you get better gas mileage on the highway is because:

1. You're driving for longer periods of time (you use more gas when the engine is cold)
2. You aren't constantly speeding up/slowing down. (you don't stop, then accelerate again.)


I'ts pretty evident by watching the DIC on my car when doing regular driving and highway driving. At 55 MPH my DIC reads anywhere from 34-42 MPG instant. At 75 that figure drops down to around 31 MPG. Above 80 and my fuel mileage drops down to only 27 MPG instant. So yes, even if I did hold 80 MPG for an extended highway trip, I'd still average out to 27, which is better than city driving. At city speeds (35-40 MPH) I can around 45 MPG instant. So yeah, if the speed limits were in fact lower, gas would be saved.


I am NOT saying I think they should be lowered, but saying she doesn't know anything isn't completely right.. You do get much better fuel economy at speeds below 60 MPH than our current speed limits on many highways.

I'm not hear to argue about this but I know the facts.

If you stay at a constant speed that would mean you are driving for longer periods of time. Hence why I said:

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I can already see this topic going down the tube...

I'm not disagreeing that you get better mileage at consitent speeds, I'm arguing that it is not correct to assume that you get the same mileage regardless of speeds, that just is not correct. How can you figure you'd get the same mileage at 55MPH VS 80 MPH when the RPM'* are higher, requiring more fuel to keep the engine revving at that speed, plus the fact that there'* more wind resistance at those speeds. It'* just not going to happen. There is nothing playing in your favor for better mileage at higher speeds (other than driving for longer periods of time, yeah.)

BTW, I don't see the topic going "down the tube" because it'* a debate. A debate isn't a bad thing at all as long as people don't personally attack each other, which I haven't seen happen yet. Gotta have data and facts to support an argument. If those aren't there, the argument is weak.

I guess it depends on what I am driving.

Jetta, supercharged, sequential EFI, gets 32-35 on the freeway at any speed that won't get me arrested. (drops to 10 or 11 at the track.

Rabbit, NA, twin carbs, big cam, etc.., 26 in town 26 freeway.

Truck, NA big v8, 7000lbs with the aerodynamics of a barn, 8-10 in town, 13 on the freeway at 55 and under, dropping to 6-8 at 65.

exactly

I enjoy trying to get high mileage on a trip. I do agree with Custom on his analysis.

I drive to Detroit from DC twice a year and consistently get 30 MPG on the way there and 33 MPG on the way back. The reason being I go from sea level up into the mountains heading to Detroit and go from the higher elevation of Michigan back down to sea level on the way back.

Yes I go have to climb into the mountains around Pittsburgh but it is easier from the higher elevation in Ohio.

BTW I am usually doing 65 to 75 MPH. The Ohio state police leave you alone if you are in the right lane and not weaving in and out of traffic trying to pass other vehicles.

The fact is it is ridiculous to try and impose such a law. "City" driving (however you want to characterize that ) waists more gas, so maybe Hillary should ban all driving that consists of more than 10 stops during a trip...

Who cares about the stinking mileage...we have high performance cars!!! If you want mileage, then buy and drive a Geo Metro!!!