Regarding the fuel efficiency numbers for the garbage trucks, a couple things to point out. The really low numbers are likely from when the trucks are doing their rounds--stopping every 100 feet, collecting the cans, accelerating toward the next house, lather, rinse, repeat. I can see how that consumes lots of fuel (hey, this sounds like a perfect application for a hybrid engine!). Once they're on the road, though, I imagine the mileage is much higher. Still, though, you have to keep in mind that these are very large, industrial machines, filled with a payload of compacted garbage, rather than a mostly-empty mid-size SUV. A H3 weighs about 2.2 tons. A garbage truck? 15-32 tons.
IIRC, the original (military-spec) hummer got 3-5mpg.
IIRC, the original (military-spec) hummer got 3-5mpg.