[Patrick]

On a recent vacation I had the opportunity to draft a semi at 75-80 mph for several miles in my 2010 Prius. As you can see (hopefully) from the pictures, I was averaging over 100 mpg for at least 20 minutes. The wider bars in the graph at the right of the display are each 5 minute averages and go up to the 100 mpg level. I was keeping about a 1 second following distance and had no problem reacting to changes by the semi driver. This was in southeastern Wyoming and I was following a North American Van Lines semi. Mileage in free air at the same speed was about 40.