My 2017 Ford Focus has gotten as much as 51 mpg and routinely gets 42-43 mpg on highway trips. Not bad considering I paid about half the cost of a Prius o buy it.
That’s pretty good, at 70 not 85
Mph a Prius will do 65 mpg. Up the speed to a cruise set 85 mph which is ten over Texas max speed limits and the defacto wink wink ok cops will let you pass them with and it drops to 56mpg. What speeds where you running on the motorway to see 40s? My S60 at 75 is lucky to see 30 mpg the Expedition is 18 mpg at those speeds and the F250 diesel is in the 15s above 70 mph. The Tesla is using 250 watt hours per mile at 75 half that at 50 air resistance is the reason it goes up logarithmic with speed.