The shipping industry provides a hefty investment into the fueling companies in America and around the world. Many transportation and semi-truck companies have started using cardlock fueling stations to have more control over fuel costs. The idea is simple. There is a network of fueling stations that form the cardlock system. Each driver and truck is issued a company specific fueling card which serves as a line of credit. This card allows the driver to use fueling stations which are not open to the public.