In reply to:

---

The issue is not how much gas these vehicles burn but how much pollution they produce.

Why then are the discussions in miles per gallon and not CO2 emissions

---

Because the 2 figures pretty much track one with the other and MPG is easier for people to understand and recite.

[And its interesting to note that MPG figures were only made a legal requirement of the Detroit car makers and published along with other information about the car, after the Oil Shocks of 1973 - Detroit resisted the MPG figures thing for as long as it could - but thats another thread].

In actual fact SUV's emit more pollution of all types, not just CO2 per "gallon" of fuel burned than just about any other car you care to name, this is mostly due in part to the engine designs being the engine equivalent of modern dinosaurs.

And of course, if your SUV gets lower MPG, you have to burn more fuel to cover the same distance as a more fuel efficient vehicle does, thus emitting even more pollutants to get the same distance covered.

The whole reason why SUVs get away with this poor situation is that the SUV's are classed as "light trucks" and therefore are able to side-step any controls on pollutants that "regular" (i.e. non-SUV) vehicles have to meet.

And Detroit lobbies Congress very hard to ensure that this lack of pollution controls rule stays that way.