A truck drive through allows material to flow from the silo via gravity directly into the truck, maximizing the rate at which the truck can be filled. The truck drive-thru eliminates the requirement for the conveyor and other rotating equipment for filling of the trucks. Fewer pieces of rotating equipment equates to reduced maintenance costs.
Conveyors underneath the silo on the other hand can reduce the overall height of the silo required. A conveyor set up that is fed from multiple silos can reduce the overall project cost by reducing the number of scales required . A single truck scale could be fed from any one of the silos.