first, that is almost certinally not writen by Geogre Carlin. http://www.georgecarlin.com/home/home.html
for further reading about that.
Second, I doubt that the illegals are using all that much gasoline. They aren't the ones driving 50 miles each way, by themselves, in a huge SUV to work and back. I think their more likely to have 15 people stuffed into a midsized car to get to the job site.
And finally, do you really want someone fresh over the fence representing us in other countries?