Well, I principally live in
Well, I principally live in the NW, and spend considerable time in NE Texas. I also drive many trips a year of varying lengths from 250 miles to 1,500 miles, and some all the way across the country from the NW to Ft Lauderdale/Tampa. I just finished a 28 hour round trip of 500 miles today...At 45-55 MPH. The 45 MPH was over the passes in the truck lanes. Going up a steep hill in a heavy vehicle, at the speed limit, consumes one hell of a lot of fuel in a short distance, for little gain in time.
My old work trip, in my pick-up, from Portland, Or. to LA was about 950 miles. At a 55 MPH that calculates out to around 17 hours. At 65 MPH, it would be nearly 15 hours. At 55 MPH, the truck would get 15-16 MPG. At 65 MPH, it dropped to 10-11 MPG. 63 gallons at 55 MPH, versus 90 gallons at 65 MPH. I will trade a nearly 50% increase in fuel consumption for a 13% increase in travel time, every time. And at $4.00 a gallon gas, the increased cost is $108.00. And I have found, that higher trip speeds are often negated by actual conditions... Traffic, stops for food, and at least one more stop for fuel,and whatever.
Now in a high MPG car, I could of course drive faster, depending on the effect of increased speed on fuel consumption. But I generally don't. Even in Texas on 70-85 limit roads, I generally keep it somewhere between 55 and 60 MPH and enjoy the conversation, music and scenery. Besides I like too look for old cars and trucks, might miss one at the go nowhere fast speed for more money.
And fuel mileage isn't the only cost factor with a vehicle, higher speeds consume tires faster, wear out engines and transmissions, bearings, faster, and a lot of other consumables. Not to mention that column of pollution created by every burnt gallon of fuel. One gallon of fuel burned creates approximately 19 pound of pollution. I care about my impact on the planet and the condition of the environment I leave my kids, and yours.
Too many, are in a big hurry, to go nowhere fast... and we all pay for their willful lack of consideration.