El Faouzi and Lesort [7] and Sethi

El Faouzi and Lesort [7] and Sethi et al. [36] published the early papers in which a practical traffic and transportation problem was addressed as a data fusion problem. For the last 15 years, various authors have made significant contributions to the field of DF in transportation systems. ITS offers indisputably the most relevant framework for DF and also the most challenging, see e.g. [21], [22] and [23]. Others conventional problems in transportation modelling have also being concerned with multi-source processing, namely: planning problems, demand estimation, traffic estimation, etc. [37]. A variety of functions are assigned to ITS to address the traffic congestion and safety problems. These functions were designed to achieve a specific task in order to cope with an operational problem. One can mention advanced traveler information systems (ATIS), automatic incident detection (AID), advanced driver assistance (ADAS), Network control, crash analysis and prevention, traffic demand estimation, traffic forecast and monitoring and accurate position estimation. Each of these sub-systems can make use of different information sources. DF techniques can then be used to combine them to yield better results.