Speed doesn't have anything to do with mileage. My truck has an overdrive gear for a reason.
I'm sure that each car has a "sweet spot" where they mileage is maximized at a certain speed, but to argue that it's 55 MPH for every car is ridiculous. Maybe those sweet spots should be identified for each vehicle.
Maybe we need to increase the speed limit. Doesn't less driving time cut down on gas usage? Several years ago I heard a joke about a couple of women that were stopped for speeding. They were driving fast so they could get to the station before they ran out of gas. :)
My car has an overdrive, could you tell me what it's for.
I know one is for city driving and one is for highway but I don't know which is which.
Please you are embarassing yourself. Stick to stuff you know about.
You don't defeat a stupid argument with more of the same. Air resistance, which is the main variable in mileage at higher speeds, increases exponentially with speed. Double your speed and you quadruple air resistance. What the article says is factually correct. The way to argue against it is to point out that we are free people accustomed to a certain lifestyle and have priorities other than trying to knock ten percent off our gas bill.
Nowadays, many cars get their higher fuel efficency at higher speeds. For comparison, my od equipped 83 Cutlass Supreme gets 22 mpg on the highway from 68 mph up to about 85 mph, above that it drops to 18-20 mpg. My 96 Ciera SL gets 26 mpg on the highway, and does its best mileage between 75 and 90 mph, below 75 it stays around 23 mpg on the highway.
I guarantee that your truck would have a lot lower mileage wtihout that overdrive gear--probably gets 16-18 mpg now, would get 12-14 mpg otherwise.
The biggest increase in the cost of fuel for filling up a truck or SUV, is not as much an actual increase as percieved. In the 70s and 80s, trucks had 14-16 gallon tanks. Now trucks and SUVs usually have 30-40 gallon tanks (and their mileage has indeed improved some because I know older trucks usually got 10-12 mpg at best). They have much longer cruising range, but they cost more to fuel up (regardless of the fuel price) because of holding more fuel.
While the relationship is not simple, speed does have something to do with mileage. If for no other reason that wind resistance goes up roughly as the square of the speed. However efficiency of the engine-drivetrain combination may also go up. (ie. gallons of fuel per horsepower hour, to make up a, AFAIK, new unit of measure). More horsepower is required as speed increases, but it may be partially or totally balenced by increase efficiency. Some tractor-trailer rigs actually lost MPG when the speed limit was reduced in the 70s, because the gearing was designed to be most efficient at 70 MPH or so. The only way they could change that was to get a new transmission, or at least new gears for the ones they had.