The time difference on my 100 mile trip 75 vs 60 was TEN minutes, not twenty…
At the moment PRICE is being used to limit consumption. The more money you have, the faster you can drive…But sooner or later, there will simply not be enough fuel to support 80mph speeds and lower speed limits will be imposed to stretch available supplies. Your choice will be 60mph or don’t drive at all. Or perhaps, you get 12 gallons a week, drive as fast or as slow as you want…No one seems to realize we are teetering on the edge of a global fuel shortage…
You should expect about 20% better gas mileage. I go the speed limit, and you are welcome to as well no matter what anyone else says. You are not the unsafe one, those that go too fast are. I prefer to travel at the speed limit, which includes 65 MPH interstates around here. If you stay to the right, fewer people will tailgate you.
The time difference on my 100 mile trip 75 vs 60 was TEN minutes, not twenty…
Congratulations. But when you state it like a simple math problem, then it doesn’t work out that way, does it?
On a 100 mile trip, if you drive 75mph, it will take you one hour and twenty minutes to travel the distance. Slow down to 60mph and the same trip will take one hour and thirty minutes, 10 minutes more
100 miles / 75 mph = 1.3333 hr
100 miles / 60 mph = 1.6666 hr
.3333hr = 20 minutes. And that’s the BEST you could do assuming the entire trip was at the specified speed. If you can halve that time, you must live at the nexus of the universe, you are going much faster than 75 for a good part of the trip or your time estimation is way off.
Depends heavily on your car. Are you driving a brick on wheels or are you driving a cruise missle? The thing to do is what others have already said. Test it out yourself, but be advised that different engines have different minimum fuel consumption points. Depending on the gear ratio of your top gear and the drag coefficient/cross-sectional area of your car, your gas mileage will deviate from the average. If you have an especially aerodynamic car (coefficient < 0.2 - 0.3), you are incurring less of a penalty by traveling at higher speeds. Furthermore, your engine will have a minimum consumption point at a given RPM. It is possible that your fuel consumption could be, for example, 30 mpg at 55 mph, 31 mpg at 60, and 25 at 75. Depending on where your engine is on its fuel consumption curve (and how much of a loss you take due to air resistance), you may get slightly better mileage by traveling at a slightly higher speed. The rule of thumb is generally true that higher speed = higher consumption, but if you are truly interested, you can experiment and discover at exactly what speed your car will get the best fuel economy, but you would need to test it out in a controlled environment (same weather conditions, same stretch of highway, use cruise control, don’t run the AC or open the windows while testing), and test using increments of maybe 2 mph to get fine resolution. If you just test at 75 and 55, obviously you are going to see the general trend confirmed, but if you are crafty (and patient), you might realize equal (or perhaps slightly better) mileage at a higher speed, thus catering to (y)our desires to get from point A to point B in the shortest amount of time.