Open cargo bays are subdivided by means of simple partitions.

Some simple structural modifications have been demonstrated to be effective in reducing aerodynamic drag on vehicles that have empty open cargo bays. The modifications were originally intended to be made in railroad coal cars because the amounts of coal and the distances over which they are transported by railroad in the United States are so large that the resulting reduction in drag could, potentially, result in an annual saving of millions of gallons of diesel fuel.