"They put a lot of pressure on you," said Rick Strain, who hauls fuel for a living.
Instead, the Americans could find their supply lines - convoys of thousands of trucks hauling food, fuel, water and ammunition - subject to attack.
These trucks are meant to travel on rough terrain to haul fuel and ammunition.
They drive trucks that haul fuel to Army trucks, tanks and Humvees on the front.
Its biggest missions in the last two years have been hauling fuel and salt to Philadelphia in a snowstorm and training with Lithuanian troops.
A convoy of four large Army trucks used to haul ammunition and fuel was in front and the private was driving one of them.
Then a convoy of trucks braved a bitter snowstorm to haul fuel to the isolated settlement.
He usually hauls fuel or gasoline down from Cuzco.
Another transport variant, the C-109, was a C-87 converted to haul fuel.
On occasion the unit dropped propaganda leaflets and hauled fuel to France.