It's the EPA that considers it a truck, something that was absolutely planned by GM. They should amend the CAFE rules: if you make a car (like the HHR or PTC) that stretches the rules to count as a truck for CAFE purposes, then it only counts if the automaker always calls it a "truck" in all their formal publications.

But then it gets murkier still because other government agencies like NHTSA or customs have their own definitions and sometime the same vehicle is called a truck by one but a car by the others.