An expert software system has been designed and implemented to solve the problems associated with user acceptance of on board computers in heavy trucks. The resulting third generation on board computer system addresses the major marketplace issues responsible for the relatively poor market penetration for on board computer systems. The administrative cost of operating an on board computer system program has been reduced by up to 70% through automating the data management process and automatically providing fleet management with easy to read memos which document the performance of the fleet. The memos are designed for several specific management levels from the driver through the company president. Memos designed specifically for drivers are generated on an exception basis and utilize a unique “coaching” approach to help improve the driver's performance.