UPS and FedEx have led the way in surge pricing. A shipment from Washington, D.C., to a residential customer used to cost the same whether shipped in March or December, but since 2017 both carriers have now implemented “demand surcharges” for packages shipped in Q4, making December shipments significantly more expensive. Both carriers have also introduced “dimensional weight charges,” where both size and weight factor into the rate, either driving higher revenue per package or pushing shippers to reduce package sizes.