Manufacturers optimize cars for 46-58 mph, since most of the EPA Highway test and 6% of the City test are at these speeds. The 1990s pattern graphed below has probably not changed much, since the EPA test has not changed. The best efficiency was usually between 46 and 53 mph. One car's best speed was below this range, and one was above. (Spreadsheet & other data at Full study at )

ChartObject Highest Fuel Efficiency Is at 46 - 53 MPH
Cars in the 1990s

Last Updated on 3/5/2009