OT: towing vs not towing - efficiency

[koabi.brooks at gmail.com (Koabi Brooks)]

I had planned on driving a uhaul type thing down to AZ from CO while towing
a car.  Now it looks like I'll have a job interview so I am considering
driving a car down early and flying back which would free up the need for
the trailer.  Anyways I started wondering if its more efficient to tow a car
with a truck or to drive a car and the truck.  I assume that the towing
arrangement would be most efficient because you have one engine running
instead of two, but that's not really much of a conclusion.

discuss if you're bored :)