AlterNet: I Want My SUV Truth be told, most of even the largest SUVs have fuel economy standards nearly identical to a new Porsche 911 (about 20 mpg), a vehicle capable of carrying only two snotty people and a small suitcase. And according to the most recent government data, the SUV's contribution to our smog problem pales in comparison to role played by commercial diesels and aging, oil-burning passenger vehicles (gross polluters).