Urban distribution plans are typically designed a priori and are static in nature. Hence, they cannot cope with unexpected events that might occur during the plan execution, such as adverse traffic conditions or vehicle failures, thus leading to delays, higher costs and inferior customer service. This paper discusses the design considerations for a dynamic real-time Vehicle Management System (VMS) that aims at supporting logistics managers by monitoring the status of deliveries in real time and suggesting optimal re-routing strategies whenever needed due to uncontrollable external events. We present system requirements as elicited through a survey of 73 logistics companies in Greece. Drawing on these requirements, we define the architecture of the proposed system and formulate the scenarios addressed by the vehicle re-routing sub-system, which monitors distribution vehicles, detects deviations from the delivery schedule and adjusts the plan accordingly. The paper also discusses the technical implementation considerations for the implementation of the VMS in a real-life setting.