The U.S. Customs and Border Protection of Homeland Security have some advice to give commercial carriers that are crossing the borders. Their Office of Field Operations allows carriers to prepay the single-crossing user fee online before arriving at the border. Fees can be paid at the Decal/Transponder Online Procurement System. Paying fees ahead of time can save time and money because there will be less wait time which means less fuel burned. Payments are accepted at the border but there may be additional processing delays. Click the link below for more information about this.