This thesis deals with the communication network performance of the Automatic Vehicle Location (AVL) distributed database system. The Automatic Vehicle Location system is used to real-time track the movement of vehicles, traveling along a large geographical area. The full control of the movement of these vehicles requires the use of many communication systems such as Global Positioning system, Packet switching network and distributed database systems including vehicle position databases. The main goal of this thesis is to minimize the update response time in a real-time fully replicated distributed ...