2003 Prius: 507 mi / 73.8 MPG = 6.87 gallons true (~5 gallons still in tank) 105.2% * 507 mi = 533.4 miles true 533.4 / 6.87 = 77.6 MPG true 105.2% is GPS measured, calibration constant for these well worn tires. I plan to post an update after replacing the well worn, Sumitomo T4s with Yokohamas. I'll measure the new tire calibration constant and repeat the test for a longer run. This was part of the Double EPA Tank contest but I screwed up in the first 150 miles. It was clear I would wind up about 35 miles short of the 979 miles needed. But I also have a pair of Yokohamas to test as replacements for the Sumitomo T4s. If they work for the rear wheels, I'll order another set and replace the front tires. Then I'll restart the stunt drive with the new tires. Bob Wilson
