Anyone ever see this Prius spreadsheet before?

some of the titles don't show up on my screen, so i'll guess about one or two things, but basically, it looks like the EPA's calculations on how much horsepower it takes to move a car (a prius?) versus road slope (grade) and car speed. one number to look at is that, at maximum speed shown on the chart, the miles per gallon doesn't go below 22 and change.... that would look like an asymptote (limit) for all-around level road driving.

the chart is useful because it combines things like frontal area and drag coefficient, which are major determiners of fuel economy once the car's moving.

i didn't do any math on this chart, but if i recall some physics rules correctly, the aerodynamic drag goes up as the CUBE of speed, so going from 20 mph to 60 mph, the speed triples, but the aero-drag goes up by 3-cubed (3x3x3) or 27 times! this is what, in real life, limits the top speed of cars. the horsepower output of the powerplant, after all losses down to the tires hitting the pavement, equals the aerodynamic drag.

hope this helps a little, and hope it's a good guess, too.