In the Truck Load (TL) segment of the trucking industry, successful fleet management is essential to survival. Principles of fleet management include establishing effective financial controls, developing integrated operating system, developing and enhancing real-time communications systems, and managing and motivating human resources. Well-designed, reliable communications systems tie all dimensions of fleet management together.Several companies have entered the mobile satellite system industry. Typically, these systems consist of mobile satellite terminals installed in each truck, space segment and central hub facilities, hub-to-dispatch office software, and communication links. The services offered by each system may vary, depending on the implementation of these components.Most mobile satellite systems provide position determination and two-way messaging between dispatchers and their fleets. Together with computerized routing and vehicle tracking software, these systems provide both quantitative and qualitative benefits. Quantitative benefits include higher equipment utilization, reduced empty and out-of-route miles, and elimination of check calls. Qualitative benefits include improved customer service, increased driver job satisfaction, and better emergency response.The success of mobile satellite systems depends upon successful integration of logistics systems and use of Electronic Data Interchange (EDI). There are four levels of integration, with each higher level moving toward a greater merging of carriers' planning and operations with those of the shippers and receivers of goods.This discussion paper describes mobile satellite communications systems and suggests how the Intelligent Vehicle Highway System (IVHS) work can benefit from truckers' extensive use of positioning and communications systems. In closing, the discussion highlights the challenge of integrating individually developed IVHS products.