| The transportation system and the economy of a city or region are interdependent. Policies that alter transportation prices or service levels can have substantial effects on a local economy. Although transportation planners must be aware of and able to predict these impacts, very little research has been done on the subject to date. ECOTRAN, the model presented in this dissertation, considers the interactions of the economy with the transportation system that serves it, evaluates the indirect economic impacts of transportation policies, and thus fills a void in the transportation planning literature.;Two case studies were performed to demonstrate the model's application. A New York CBD study analyzed a variety of options. The results indicate that transit fare reductions are the most likely to stimulate the local economy, while parking cost increases are the most appropriate congestion relief strategies. The disadvantages produced by raising taxes for transportation improvements are outweighed by the advantages of the improvements, and property taxes are the least harmful. A Newark, NJ CBD study investigated the impacts of a free-fare zone. Through a modified version of the model, it was found that the strategy will improve the local economy and increase transit ridership, but it will not reduce congestion as the local planners expect.;ECOTRAN is written in PL/1, although its structure imitates the DYNAMO simulation language since the system it models is dynamic. It is easy and inexpensive to use and it does not require large quantities or very accurate data.;ECOTRAN is a sketch planning, iterative, and dynamic computer package that can be used to evaluate transportation policies in an economically active small area like a Central Business District (CBD). Given a transportation policy, the model predicts the impacts on the transportation system and the CBD economy. Changes in the CBD economy affect the regional economies. If a financing option is considered, its effects on the CBD and regional economies are predicted, and finally the changes in the economy have an impact on the transportation system. The process continues iteratively until the end of the desired forecasting period is reached. |
