TEST-DRIVING THE 39 MPG VW Passat TDI Diesel. “Through more than 17,000 miles of mixed driving, we’ve averaged 39 mpg. That makes the Passat the rare car with the extraordinary ability to turn Car and Driver staffers into motorists who can meet or even exceed EPA estimates. The mileage is even more impressive when you consider that we rarely modify our driving style when behind the VW’s steering wheel.”