A hybrid modeling method for the planning and evaluation of intelligent transportation systems

Intelligent Transportation Systems (ITS), with significant progressive development in the last decade, have been considered as effective ways to improve the efficiency of the transportation system. The state and local planning agencies in the US and elsewhere will soon consider ITS facilities in their transportation plans. However, ITS, which are primarily operations and information oriented, are different from the traditional "facility-based" projects. Therefore, the traditional transportation planning models are not suitable for the evaluation of ITS. In this paper, we present a hybrid modeling method which combines the use of the transportation planning model (TPM) and the traffic analysis/simulation model (TAM) with an interface. After examining the functionalities and the data used by the models, we found that TPMs and TAMs share a large amount of data in similar formats and provide most of the measures of effectiveness for the evaluation of ITS. The complementary use of TPM and TAM is discussed based on three factors: 1) the scope of the expected impacts; 2) the planning horizon; and 3) nature of the impacts (e.g., travel demand oriented or traffic operations oriented). Finally, a conceptual interface framework for converting the information between the two types of models is discussed, while various issues related to the development of the interface are explored.