The Travis Mule horizontal-discharge asphalt trailer features a dual-walled, smooth-sided aluminum design. Reciprocating floor slats unload asphalt at a rate that can be controlled at the back of the trailer or inside the cab of the truck — without using belts or raising the trailer. The 28-foot long, 4-axle trailer hauls 80,000 pounds gross in at least 37 states, says Travis, and weighs 10,998 pounds.