The method takes into account exterior package size in relation to its actual weight. The dimensional weight calculation applies if it is greater than the actual weight. UPS noted that recent electronic-commerce trends have resulted in a decrease in package density. The result is less efficient use of cargo space, and an increased cost per package. Adoption of the dimensional weight pricing method will motivate shippers to optimize their packaging practices, the company said. “These efforts will reduce excess packaging materials and overall package sizes, leading to related reductions in fuel use, vehicle emissions and transportation costs.” UPS already applies that method for its domestic and international air services, UPS Standard to Mexico ground services, and domestic ground packages measuring three cubic feet or larger.