Most semi-trailers weigh about 32,000 pounds when they are empty. Because the amount for a payload must be evenly distributed, the amount of cargo a trucker can haul is no more than 34,000 pounds if he is pulling tandem trailers.
If the driver is driving a day cab, his truck and trailer weighs less than it would if he is driving a sleeper cable. To estimate the total weight, certain items must be factored into the equation, including added cab amenities and the rigging that is used to haul the load.
Semi-trailers are available in a variety of styles, each of which can affect the total weight. Truckers haul loads on single-drop and double-drop flatbeds, in dry vans and in refrigeration units. Flatbeds typically range from 45 to 48 feet unless they are extended in which case they can span up to 75 feet in length.