Stories like this with insufficient information (no, I have not bothered to read the full article about a GM vehicle) are like the friend why says,
"My car gets GREAT gas mileage!"
"Really, how much?"
"Well, I filled up last Friday and am still showing a quarter tank remaining!"
the sad part being, of course, that by law Ugandan gas stations are 1,000 miles apart
If it wasn’t designed as a box and more aerodynamic it would even get better gas mileage.