It's possible for any vehicle to even get 99.99 mpg driving down hill without the gas pedal. I drive a 2016 full size diesel Ford van at work with a trip computer showing average mpg. On average, they show 22 mpg . But I think it's fun to get it to show a much higher average by resetting the computer at the top of a hill and let gravity do the work for you. A couple miles later at the bottom of the hill, it's reading 99.99 mpg. I hit the gas when the freeway flattens out, the reading goes down quickly, but it's reading 40mpg by the time I park the van at work. The next guy who drives the van wonders how it's getting such good mileage ?? He tries to keep that reading high, but just can't do it !!!