2003 Dodge 3500 duallie automatic 2wd, 34 ft Limited fully loaded: 55 mph on (non-mountain) interstates = an honest 15.0 mpg towing (solo at 55 = 22 mpg). But fuel costs are only a fraction of the total $.60 - $.80 per mile actual operating costs of a tow vehicle, so don't give up other more important stuff just to pick up another mpg. Jerry 4404