| Abstract | This research aims at reviewing, applying, and evaluating a promising methodology system dynamics for transportation systems analysis. Transportation systems are characterized by the large number of variables, dynamic nature, nonlinearity, and feedback. Thus, system dynamics may be able to do for transportation systems what it has done for other socio technological systems to elaborate a system theory whose generality and content are so balanced as to yield extensive application within a field. Six diverse problem areas including the dynamics of the traffic stream, signalization analysis, port operations, the growth of highway transporta tion. the decline of urban public transit, and transportation and land use interactions have been selected for analysis using the system dynamics methodology. The intent is not to try to solve six contrived problems but to isolate an approach to understanding all of them. For example, each of the system dynamics models developed for studying these six problems consists of information and physical flows. The physical flows may be broken down into transportation demand, throughput, funds, people, and capital (units of carriage and fixed facilities). A similar format is used in the approach to each problem area: (1) the nature of the problem is described; (2) causal relationships and feedbacks between key variables are isolated; (3) the model is des cribed is three complementary forms verbal, graphical using system dynamics symbols, and mathematical using DYNAMO equations; (4) results are presented in the form of computer tables and graphical plots; and (5) the extensions and significance are discussed. The application of the methodology to investigating rather simple technological and policy alternatives is illustrated in each case. Possible extensions of each of the six models are suggested as well as ways in which the models can be combined to address other, more comprehensive problem. are indicated. Throughout the presentation, emphasis is placed on the potential of the system dynamics methodology for solving problems in developing countries. |