Hauled Peterbilt's custom modified trailer (with load of concrete blocks used in testing phase of 10.7 mpg "Super Truck" with roof fairing for same truck) to Maryland for President Obama's speech on truck fuel efficiency. "Super Truck" and trailer was a backdrop to his speech. Then hauled same trailer at Peterbilt request to Kenworth plant for preperation to be shown at Paccar corporate offices. Returned two weeks later to take same trailer to Columbus, IN for pre-staging for Mid America truck show. A lot of miles with the same trailer / load. Truly enjoyed having them as a customer, especially as a company driver. Even averaged 1.5 mpg better then normal! Trip end average with just "trailer mods and 61200 gross" was 8.6 mpg! It definitely WORKS!