1 Census 2010 Race for Effingham County, Illinois. 2  Census 2010 Latino for Effingham County, Illinois. 3  Census 2000 Race for Effingham County, Illinois. 4  Census 2000 Latino for Effingham County, Illinois.  Illinois Voters for Effingham County, Illinois.
On average, a truck traveling at 65 mph instead of 75 mph will experience up to 27-percent improvement in fuel consumption. As a rule of thumb, for every one mile per hour increase in speed, there is a corresponding 0.14 mile-per-gallon (mpg) fuel consumption penalty, says Kedzie.
While each vehicle reaches its optimal fuel economy at a different speed (or range of speeds), gas mileage usually decreases rapidly speeds above 55 miles per hour. Just slowing down from 65 mph to 55 mph can increase your miles per gallon by as much as 15 percent.According to the U.S. Department of Energy (DOE), as a rule of thumb, you can assume that each 5 mph you drive over 60 mph is like paying an additional $0.21 per gallon for gas (at $3.00 per gallon).hile each vehicle reaches its optimal fuel economy at a different speed (or range of speeds), gas mileage usually decreases rapidly speeds above 55 miles per hour. Just slowing down from 65 mph to 55 mph can increase your miles per gallon by as much as 15 percent.