Intelligent Transportation Systems (ITSs) are built considering numerous legal regulations, organisational conditions, and user needs. For this reason, they cannot be sold as plug & play products and their implementation requires a clear definition of functional and technical requirements. The primary objective of ITSs is to improve the efficiency and safety of road traffic. In fact, nowadays, the number of motorways all over Europe is increasing. The road freight transport is also growing. These are one of some reasons of caused accidents. Solution to this problem may be implementation of ITS systems. But, a reliable work of them is possible when their reliability is at a very high level. The aim of this paper is to present a new model of reliability and operation analysis of the selected ITS system which include continuous provision of power to its elements. The article also contains a logical, functional and physical viewpoint of selected ITS system.